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node_modules/mammoth/lib/docx/body-reader.js

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+exports.createBodyReader = createBodyReader;
+exports._readNumberingProperties = readNumberingProperties;
+
+var dingbatToUnicode = require("dingbat-to-unicode");
+var _ = require("underscore");
+
+var documents = require("../documents");
+var Result = require("../results").Result;
+var warning = require("../results").warning;
+var xml = require("../xml");
+var transforms = require("../transforms");
+var uris = require("./uris");
+
+function createBodyReader(options) {
+    return {
+        readXmlElement: function(element) {
+            return new BodyReader(options).readXmlElement(element);
+        },
+        readXmlElements: function(elements) {
+            return new BodyReader(options).readXmlElements(elements);
+        }
+    };
+}
+
+function BodyReader(options) {
+    var complexFieldStack = [];
+    var currentInstrText = [];
+
+    // When a paragraph is marked as deleted, its contents should be combined
+    // with the following paragraph. See 17.13.5.15 del (Deleted Paragraph) of
+    // ECMA-376 4th edition Part 1.
+    var deletedParagraphContents = [];
+
+    var relationships = options.relationships;
+    var contentTypes = options.contentTypes;
+    var docxFile = options.docxFile;
+    var files = options.files;
+    var numbering = options.numbering;
+    var styles = options.styles;
+
+    function readXmlElements(elements) {
+        var results = elements.map(readXmlElement);
+        return combineResults(results);
+    }
+
+    function readXmlElement(element) {
+        if (element.type === "element") {
+            var handler = xmlElementReaders[element.name];
+            if (handler) {
+                return handler(element);
+            } else if (!Object.prototype.hasOwnProperty.call(ignoreElements, element.name)) {
+                var message = warning("An unrecognised element was ignored: " + element.name);
+                return emptyResultWithMessages([message]);
+            }
+        }
+        return emptyResult();
+    }
+
+    function readParagraphProperties(element) {
+        return readParagraphStyle(element).map(function(style) {
+            return {
+                type: "paragraphProperties",
+                styleId: style.styleId,
+                styleName: style.name,
+                alignment: element.firstOrEmpty("w:jc").attributes["w:val"],
+                numbering: readNumberingProperties(style.styleId, element.firstOrEmpty("w:numPr"), numbering),
+                indent: readParagraphIndent(element.firstOrEmpty("w:ind"))
+            };
+        });
+    }
+
+    function readParagraphIndent(element) {
+        return {
+            start: element.attributes["w:start"] || element.attributes["w:left"],
+            end: element.attributes["w:end"] || element.attributes["w:right"],
+            firstLine: element.attributes["w:firstLine"],
+            hanging: element.attributes["w:hanging"]
+        };
+    }
+
+    function readRunProperties(element) {
+        return readRunStyle(element).map(function(style) {
+            var fontSizeString = element.firstOrEmpty("w:sz").attributes["w:val"];
+            // w:sz gives the font size in half points, so halve the value to get the size in points
+            var fontSize = /^[0-9]+$/.test(fontSizeString) ? parseInt(fontSizeString, 10) / 2 : null;
+
+            return {
+                type: "runProperties",
+                styleId: style.styleId,
+                styleName: style.name,
+                verticalAlignment: element.firstOrEmpty("w:vertAlign").attributes["w:val"],
+                font: element.firstOrEmpty("w:rFonts").attributes["w:ascii"],
+                fontSize: fontSize,
+                isBold: readBooleanElement(element.first("w:b")),
+                isUnderline: readUnderline(element.first("w:u")),
+                isItalic: readBooleanElement(element.first("w:i")),
+                isStrikethrough: readBooleanElement(element.first("w:strike")),
+                isAllCaps: readBooleanElement(element.first("w:caps")),
+                isSmallCaps: readBooleanElement(element.first("w:smallCaps")),
+                highlight: readHighlightValue(element.firstOrEmpty("w:highlight").attributes["w:val"])
+            };
+        });
+    }
+
+    function readUnderline(element) {
+        if (element) {
+            var value = element.attributes["w:val"];
+            return value !== undefined && value !== "false" && value !== "0" && value !== "none";
+        } else {
+            return false;
+        }
+    }
+
+    function readBooleanElement(element) {
+        if (element) {
+            var value = element.attributes["w:val"];
+            return value !== "false" && value !== "0";
+        } else {
+            return false;
+        }
+    }
+
+    function readBooleanAttributeValue(value) {
+        return value !== "false" && value !== "0";
+    }
+
+    function readHighlightValue(value) {
+        if (!value || value === "none") {
+            return null;
+        } else {
+            return value;
+        }
+    }
+
+    function readParagraphStyle(element) {
+        return readStyle(element, "w:pStyle", "Paragraph", styles.findParagraphStyleById);
+    }
+
+    function readRunStyle(element) {
+        return readStyle(element, "w:rStyle", "Run", styles.findCharacterStyleById);
+    }
+
+    function readTableStyle(element) {
+        return readStyle(element, "w:tblStyle", "Table", styles.findTableStyleById);
+    }
+
+    function readStyle(element, styleTagName, styleType, findStyleById) {
+        var messages = [];
+        var styleElement = element.first(styleTagName);
+        var styleId = null;
+        var name = null;
+        if (styleElement) {
+            styleId = styleElement.attributes["w:val"];
+            if (styleId) {
+                var style = findStyleById(styleId);
+                if (style) {
+                    name = style.name;
+                } else {
+                    messages.push(undefinedStyleWarning(styleType, styleId));
+                }
+            }
+        }
+        return elementResultWithMessages({styleId: styleId, name: name}, messages);
+    }
+
+    function readFldChar(element) {
+        var type = element.attributes["w:fldCharType"];
+        if (type === "begin") {
+            complexFieldStack.push({type: "begin", fldChar: element});
+            currentInstrText = [];
+        } else if (type === "end") {
+            if (complexFieldStack.length === 0) {
+                return emptyResultWithMessages([warning(
+                    "Ignoring complex field end character without corresponding start character"
+                )]);
+            }
+
+            var complexFieldEnd = complexFieldStack.pop();
+            if (complexFieldEnd.type === "begin") {
+                complexFieldEnd = parseCurrentInstrText(complexFieldEnd);
+            }
+            if (complexFieldEnd.type === "checkbox") {
+                return elementResult(documents.checkbox({
+                    checked: complexFieldEnd.checked
+                }));
+            }
+        } else if (type === "separate") {
+            if (complexFieldStack.length === 0) {
+                return emptyResultWithMessages([warning(
+                    "Ignoring complex field separator character without corresponding start character"
+                )]);
+            }
+
+            var complexFieldSeparate = complexFieldStack.pop();
+            var complexField = parseCurrentInstrText(complexFieldSeparate);
+            complexFieldStack.push(complexField);
+        }
+        return emptyResult();
+    }
+
+    function currentHyperlinkOptions() {
+        var topHyperlink = _.last(complexFieldStack.filter(function(complexField) {
+            return complexField.type === "hyperlink";
+        }));
+        return topHyperlink ? topHyperlink.options : null;
+    }
+
+    function parseCurrentInstrText(complexField) {
+        return parseInstrText(
+            currentInstrText.join(''),
+            complexField.type === "begin"
+                ? complexField.fldChar
+                : xml.emptyElement
+        );
+    }
+
+    function parseInstrText(instrText, fldChar) {
+        var linkResult = /^\s*HYPERLINK\s+(\\l\s+)?(?:"(.*)"|([^\\]\S*))/.exec(instrText);
+        if (linkResult) {
+            var location = linkResult[2] === undefined ? linkResult[3] : linkResult[2];
+            var options = linkResult[1] === undefined ? {href: location} : {anchor: location};
+            return {type: "hyperlink", options: options};
+        }
+
+        var checkboxResult = /\s*FORMCHECKBOX\s*/.exec(instrText);
+        if (checkboxResult) {
+            var checkboxElement = fldChar
+                .firstOrEmpty("w:ffData")
+                .firstOrEmpty("w:checkBox");
+            var checkedElement = checkboxElement.first("w:checked");
+            var checked = checkedElement == null
+                ? readBooleanElement(checkboxElement.first("w:default"))
+                : readBooleanElement(checkedElement);
+            return {type: "checkbox", checked: checked};
+        }
+
+        return {type: "unknown"};
+    }
+
+    function readInstrText(element) {
+        currentInstrText.push(element.text());
+        return emptyResult();
+    }
+
+    function readSymbol(element) {
+        // See 17.3.3.30 sym (Symbol Character) of ECMA-376 4th edition Part 1
+        var font = element.attributes["w:font"];
+        var char = element.attributes["w:char"];
+        var unicodeCharacter = dingbatToUnicode.hex(font, char);
+        if (unicodeCharacter == null && /^F0..$/.test(char)) {
+            unicodeCharacter = dingbatToUnicode.hex(font, char.substring(2));
+        }
+
+        if (unicodeCharacter == null) {
+            return emptyResultWithMessages([warning(
+                "A w:sym element with an unsupported character was ignored: char " +  char + " in font " + font
+            )]);
+        } else {
+            return elementResult(new documents.Text(unicodeCharacter.string));
+        }
+    }
+
+    function noteReferenceReader(noteType) {
+        return function(element) {
+            var noteId = element.attributes["w:id"];
+            return elementResult(new documents.NoteReference({
+                noteType: noteType,
+                noteId: noteId
+            }));
+        };
+    }
+
+    function readCommentReference(element) {
+        return elementResult(documents.commentReference({
+            commentId: element.attributes["w:id"]
+        }));
+    }
+
+    function readChildElements(element) {
+        return readXmlElements(element.children);
+    }
+
+    var xmlElementReaders = {
+        "w:p": function(element) {
+            var paragraphPropertiesElement = element.firstOrEmpty("w:pPr");
+
+            var isDeleted = !!paragraphPropertiesElement
+                .firstOrEmpty("w:rPr")
+                .first("w:del");
+
+            if (isDeleted) {
+                element.children.forEach(function(child) {
+                    deletedParagraphContents.push(child);
+                });
+                return emptyResult();
+            } else {
+                var childrenXml = element.children;
+                if (deletedParagraphContents.length > 0) {
+                    childrenXml = deletedParagraphContents.concat(childrenXml);
+                    deletedParagraphContents = [];
+                }
+                return ReadResult.map(
+                    readParagraphProperties(paragraphPropertiesElement),
+                    readXmlElements(childrenXml),
+                    function(properties, children) {
+                        return new documents.Paragraph(children, properties);
+                    }
+                ).insertExtra();
+            }
+        },
+        "w:r": function(element) {
+            return ReadResult.map(
+                readRunProperties(element.firstOrEmpty("w:rPr")),
+                readXmlElements(element.children),
+                function(properties, children) {
+                    var hyperlinkOptions = currentHyperlinkOptions();
+                    if (hyperlinkOptions !== null) {
+                        children = [new documents.Hyperlink(children, hyperlinkOptions)];
+                    }
+
+                    return new documents.Run(children, properties);
+                }
+            );
+        },
+        "w:fldChar": readFldChar,
+        "w:instrText": readInstrText,
+        "w:t": function(element) {
+            return elementResult(new documents.Text(element.text()));
+        },
+        "w:tab": function(element) {
+            return elementResult(new documents.Tab());
+        },
+        "w:noBreakHyphen": function() {
+            return elementResult(new documents.Text("\u2011"));
+        },
+        "w:softHyphen": function(element) {
+            return elementResult(new documents.Text("\u00AD"));
+        },
+        "w:sym": readSymbol,
+        "w:hyperlink": function(element) {
+            var relationshipId = element.attributes["r:id"];
+            var anchor = element.attributes["w:anchor"];
+            return readXmlElements(element.children).map(function(children) {
+                function create(options) {
+                    var targetFrame = element.attributes["w:tgtFrame"] || null;
+
+                    return new documents.Hyperlink(
+                        children,
+                        _.extend({targetFrame: targetFrame}, options)
+                    );
+                }
+
+                if (relationshipId) {
+                    var href = relationships.findTargetByRelationshipId(relationshipId);
+                    if (anchor) {
+                        href = uris.replaceFragment(href, anchor);
+                    }
+                    return create({href: href});
+                } else if (anchor) {
+                    return create({anchor: anchor});
+                } else {
+                    return children;
+                }
+            });
+        },
+        "w:tbl": readTable,
+        "w:tr": readTableRow,
+        "w:tc": readTableCell,
+        "w:footnoteReference": noteReferenceReader("footnote"),
+        "w:endnoteReference": noteReferenceReader("endnote"),
+        "w:commentReference": readCommentReference,
+        "w:br": function(element) {
+            var breakType = element.attributes["w:type"];
+            if (breakType == null || breakType === "textWrapping") {
+                return elementResult(documents.lineBreak);
+            } else if (breakType === "page") {
+                return elementResult(documents.pageBreak);
+            } else if (breakType === "column") {
+                return elementResult(documents.columnBreak);
+            } else {
+                return emptyResultWithMessages([warning("Unsupported break type: " + breakType)]);
+            }
+        },
+        "w:bookmarkStart": function(element){
+            var name = element.attributes["w:name"];
+            if (name === "_GoBack") {
+                return emptyResult();
+            } else {
+                return elementResult(new documents.BookmarkStart({name: name}));
+            }
+        },
+
+        "mc:AlternateContent": function(element) {
+            return readChildElements(element.firstOrEmpty("mc:Fallback"));
+        },
+
+        "w:sdt": function(element) {
+            var contentResult = readXmlElements(element.firstOrEmpty("w:sdtContent").children);
+            return contentResult.map(function(content) {
+                // From the WordML standard: https://learn.microsoft.com/en-us/openspecs/office_standards/ms-docx/3350cb64-931f-41f7-8824-f18b2568ce66
+                //
+                // > A CT_SdtCheckbox element that specifies that the parent
+                // > structured document tag is a checkbox when displayed in the
+                // > document. The parent structured document tag contents MUST
+                // > contain a single character and optionally an additional
+                // > character in a deleted run.
+
+                var checkbox = element
+                    .firstOrEmpty("w:sdtPr")
+                    .first("wordml:checkbox");
+
+                if (checkbox) {
+                    var checkedElement = checkbox.first("wordml:checked");
+                    var isChecked = !!checkedElement && readBooleanAttributeValue(
+                        checkedElement.attributes["wordml:val"]
+                    );
+                    var documentCheckbox = documents.checkbox({
+                        checked: isChecked
+                    });
+
+                    var hasCheckbox = false;
+                    var replacedContent = content.map(transforms._elementsOfType(
+                        documents.types.text,
+                        function(text) {
+                            if (text.value.length > 0 && !hasCheckbox) {
+                                hasCheckbox = true;
+                                return documentCheckbox;
+                            } else {
+                                return text;
+                            }
+                        }
+                    ));
+
+                    if (hasCheckbox) {
+                        return replacedContent;
+                    } else {
+                        return documentCheckbox;
+                    }
+
+                } else {
+                    return content;
+                }
+            });
+        },
+
+        "w:customXml": readChildElements,
+        "w:ins": readChildElements,
+        "w:moveFromRangeEnd": readChildElements,
+        "w:moveFromRangeStart": readChildElements,
+        "w:moveTo": readChildElements,
+        "w:moveToRangeEnd": readChildElements,
+        "w:moveToRangeStart": readChildElements,
+        "w:object": readChildElements,
+        "w:smartTag": readChildElements,
+        "w:drawing": readChildElements,
+        "w:pict": function(element) {
+            return readChildElements(element).toExtra();
+        },
+        "v:roundrect": readChildElements,
+        "v:shape": readChildElements,
+        "v:textbox": readChildElements,
+        "w:txbxContent": readChildElements,
+        "wp:inline": readDrawingElement,
+        "wp:anchor": readDrawingElement,
+        "v:imagedata": readImageData,
+        "v:group": readChildElements,
+        "v:rect": readChildElements
+    };
+
+    return {
+        readXmlElement: readXmlElement,
+        readXmlElements: readXmlElements
+    };
+
+
+    function readTable(element) {
+        var propertiesResult = readTableProperties(element.firstOrEmpty("w:tblPr"));
+        return readXmlElements(element.children)
+            .flatMap(calculateRowSpans)
+            .flatMap(function(children) {
+                return propertiesResult.map(function(properties) {
+                    return documents.Table(children, properties);
+                });
+            });
+    }
+
+    function readTableProperties(element) {
+        return readTableStyle(element).map(function(style) {
+            return {
+                styleId: style.styleId,
+                styleName: style.name
+            };
+        });
+    }
+
+    function readTableRow(element) {
+        var properties = element.firstOrEmpty("w:trPr");
+
+        // See 17.13.5.12 del (Deleted Table Row) of ECMA-376 4th edition Part 1
+        var isDeleted = !!properties.first("w:del");
+        if (isDeleted) {
+            return emptyResult();
+        }
+
+        var isHeader = !!properties.first("w:tblHeader");
+        return readXmlElements(element.children).map(function(children) {
+            return documents.TableRow(children, {isHeader: isHeader});
+        });
+    }
+
+    function readTableCell(element) {
+        return readXmlElements(element.children).map(function(children) {
+            var properties = element.firstOrEmpty("w:tcPr");
+
+            var gridSpan = properties.firstOrEmpty("w:gridSpan").attributes["w:val"];
+            var colSpan = gridSpan ? parseInt(gridSpan, 10) : 1;
+
+            var cell = documents.TableCell(children, {colSpan: colSpan});
+            cell._vMerge = readVMerge(properties);
+            return cell;
+        });
+    }
+
+    function readVMerge(properties) {
+        var element = properties.first("w:vMerge");
+        if (element) {
+            var val = element.attributes["w:val"];
+            return val === "continue" || !val;
+        } else {
+            return null;
+        }
+    }
+
+    function calculateRowSpans(rows) {
+        var unexpectedNonRows = _.any(rows, function(row) {
+            return row.type !== documents.types.tableRow;
+        });
+        if (unexpectedNonRows) {
+            removeVMergeProperties(rows);
+            return elementResultWithMessages(rows, [warning(
+                "unexpected non-row element in table, cell merging may be incorrect"
+            )]);
+        }
+        var unexpectedNonCells = _.any(rows, function(row) {
+            return _.any(row.children, function(cell) {
+                return cell.type !== documents.types.tableCell;
+            });
+        });
+        if (unexpectedNonCells) {
+            removeVMergeProperties(rows);
+            return elementResultWithMessages(rows, [warning(
+                "unexpected non-cell element in table row, cell merging may be incorrect"
+            )]);
+        }
+
+        var columns = {};
+
+        rows.forEach(function(row) {
+            var cellIndex = 0;
+            row.children.forEach(function(cell) {
+                if (cell._vMerge && columns[cellIndex]) {
+                    columns[cellIndex].rowSpan++;
+                } else {
+                    columns[cellIndex] = cell;
+                    cell._vMerge = false;
+                }
+                cellIndex += cell.colSpan;
+            });
+        });
+
+        rows.forEach(function(row) {
+            row.children = row.children.filter(function(cell) {
+                return !cell._vMerge;
+            });
+            row.children.forEach(function(cell) {
+                delete cell._vMerge;
+            });
+        });
+
+        return elementResult(rows);
+    }
+
+    function removeVMergeProperties(rows) {
+        rows.forEach(function(row) {
+            var cells = transforms.getDescendantsOfType(row, documents.types.tableCell);
+            cells.forEach(function(cell) {
+                delete cell._vMerge;
+            });
+        });
+    }
+
+    function readDrawingElement(element) {
+        var blips = element
+            .getElementsByTagName("a:graphic")
+            .getElementsByTagName("a:graphicData")
+            .getElementsByTagName("pic:pic")
+            .getElementsByTagName("pic:blipFill")
+            .getElementsByTagName("a:blip");
+
+        return combineResults(blips.map(readBlip.bind(null, element)));
+    }
+
+    function readBlip(element, blip) {
+        var propertiesElement = element.firstOrEmpty("wp:docPr");
+        var properties = propertiesElement.attributes;
+
+        var altText = isBlank(properties.descr) ? properties.title : properties.descr;
+
+        var blipImageFile = findBlipImageFile(blip);
+        if (blipImageFile === null) {
+            return emptyResultWithMessages([warning("Could not find image file for a:blip element")]);
+        }
+
+        return readImage(blipImageFile, altText).map(function(imageElement) {
+            var hlinkClickElement = propertiesElement.firstOrEmpty("a:hlinkClick");
+            var relationshipId = hlinkClickElement.attributes["r:id"];
+            if (relationshipId) {
+                var href = relationships.findTargetByRelationshipId(relationshipId);
+                return new documents.Hyperlink([imageElement], {href: href});
+            } else {
+                return imageElement;
+            }
+        });
+    }
+
+    function isBlank(value) {
+        return value == null || /^\s*$/.test(value);
+    }
+
+    function findBlipImageFile(blip) {
+        var embedRelationshipId = blip.attributes["r:embed"];
+        var linkRelationshipId = blip.attributes["r:link"];
+        if (embedRelationshipId) {
+            return findEmbeddedImageFile(embedRelationshipId);
+        } else if (linkRelationshipId) {
+            var imagePath = relationships.findTargetByRelationshipId(linkRelationshipId);
+            return {
+                path: imagePath,
+                read: files.read.bind(files, imagePath)
+            };
+        } else {
+            return null;
+        }
+    }
+
+    function readImageData(element) {
+        var relationshipId = element.attributes['r:id'];
+
+        if (relationshipId) {
+            return readImage(
+                findEmbeddedImageFile(relationshipId),
+                element.attributes["o:title"]);
+        } else {
+            return emptyResultWithMessages([warning("A v:imagedata element without a relationship ID was ignored")]);
+        }
+    }
+
+    function findEmbeddedImageFile(relationshipId) {
+        var path = uris.uriToZipEntryName("word", relationships.findTargetByRelationshipId(relationshipId));
+        return {
+            path: path,
+            read: docxFile.read.bind(docxFile, path)
+        };
+    }
+
+    function readImage(imageFile, altText) {
+        var contentType = contentTypes.findContentType(imageFile.path);
+
+        var image = documents.Image({
+            readImage: imageFile.read,
+            altText: altText,
+            contentType: contentType
+        });
+        var warnings = supportedImageTypes[contentType] ?
+            [] : warning("Image of type " + contentType + " is unlikely to display in web browsers");
+        return elementResultWithMessages(image, warnings);
+    }
+
+    function undefinedStyleWarning(type, styleId) {
+        return warning(
+            type + " style with ID " + styleId + " was referenced but not defined in the document");
+    }
+}
+
+
+function readNumberingProperties(styleId, element, numbering) {
+    var level = element.firstOrEmpty("w:ilvl").attributes["w:val"];
+    var numId = element.firstOrEmpty("w:numId").attributes["w:val"];
+    if (level !== undefined && numId !== undefined) {
+        return numbering.findLevel(numId, level);
+    }
+
+    if (styleId != null) {
+        var levelByStyleId = numbering.findLevelByParagraphStyleId(styleId);
+        if (levelByStyleId != null) {
+            return levelByStyleId;
+        }
+    }
+
+    // Some malformed documents define numbering levels without an index, and
+    // reference the numbering using a w:numPr element without a w:ilvl child.
+    // To handle such cases, we assume a level of 0 as a fallback.
+    if (numId !== undefined) {
+        return numbering.findLevel(numId, "0");
+    }
+
+    return null;
+}
+
+var supportedImageTypes = {
+    "image/png": true,
+    "image/gif": true,
+    "image/jpeg": true,
+    "image/svg+xml": true,
+    "image/tiff": true
+};
+
+var ignoreElements = {
+    "office-word:wrap": true,
+    "v:shadow": true,
+    "v:shapetype": true,
+    "w:annotationRef": true,
+    "w:bookmarkEnd": true,
+    "w:sectPr": true,
+    "w:proofErr": true,
+    "w:lastRenderedPageBreak": true,
+    "w:commentRangeStart": true,
+    "w:commentRangeEnd": true,
+    "w:del": true,
+    "w:footnoteRef": true,
+    "w:endnoteRef": true,
+    "w:moveFrom": true,
+    "w:pPr": true,
+    "w:rPr": true,
+    "w:tblPr": true,
+    "w:tblGrid": true,
+    "w:trPr": true,
+    "w:tcPr": true
+};
+
+function emptyResultWithMessages(messages) {
+    return new ReadResult(null, null, messages);
+}
+
+function emptyResult() {
+    return new ReadResult(null);
+}
+
+function elementResult(element) {
+    return new ReadResult(element);
+}
+
+function elementResultWithMessages(element, messages) {
+    return new ReadResult(element, null, messages);
+}
+
+function ReadResult(element, extra, messages) {
+    this.value = element || [];
+    this.extra = extra || [];
+    this._result = new Result({
+        element: this.value,
+        extra: extra
+    }, messages);
+    this.messages = this._result.messages;
+}
+
+ReadResult.prototype.toExtra = function() {
+    return new ReadResult(null, joinElements(this.extra, this.value), this.messages);
+};
+
+ReadResult.prototype.insertExtra = function() {
+    var extra = this.extra;
+    if (extra && extra.length) {
+        return new ReadResult(joinElements(this.value, extra), null, this.messages);
+    } else {
+        return this;
+    }
+};
+
+ReadResult.prototype.map = function(func) {
+    var result = this._result.map(function(value) {
+        return func(value.element);
+    });
+    return new ReadResult(result.value, this.extra, result.messages);
+};
+
+ReadResult.prototype.flatMap = function(func) {
+    var result = this._result.flatMap(function(value) {
+        return func(value.element)._result;
+    });
+    return new ReadResult(result.value.element, joinElements(this.extra, result.value.extra), result.messages);
+};
+
+ReadResult.map = function(first, second, func) {
+    return new ReadResult(
+        func(first.value, second.value),
+        joinElements(first.extra, second.extra),
+        first.messages.concat(second.messages)
+    );
+};
+
+function combineResults(results) {
+    var result = Result.combine(_.pluck(results, "_result"));
+    return new ReadResult(
+        _.flatten(_.pluck(result.value, "element")),
+        _.filter(_.flatten(_.pluck(result.value, "extra")), identity),
+        result.messages
+    );
+}
+
+function joinElements(first, second) {
+    return _.flatten([first, second]);
+}
+
+function identity(value) {
+    return value;
+}