56 lines
1.9 KiB
JavaScript
56 lines
1.9 KiB
JavaScript
"use strict";
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const anyIntersection = require("./anyIntersection");
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const fill = require("./fill");
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// Merge text part information within a styling fragment
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function assign(textPart, fragment) {
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const fragStart = fragment.start;
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const start = Math.max(fragment.start, textPart.start);
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const end = Math.min(fragment.end, textPart.end);
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const text = fragment.text.slice(start - fragStart, end - fragStart);
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return Object.assign({}, fragment, {start, end, text});
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}
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function sortParts(a, b) {
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return a.start - b.start || b.end - a.end;
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}
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// Merge the style fragments within the text parts, taking into account
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// boundaries and text sections that have not matched to links or channels.
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// For example, given a string "foobar" where "foo" and "bar" have been
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// identified as parts (channels, links, etc.) and "fo", "ob" and "ar" have 3
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// different styles, the first resulting part will contain fragments "fo" and
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// "o", and the second resulting part will contain "b" and "ar". "o" and "b"
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// fragments will contain duplicate styling attributes.
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function merge(textParts, styleFragments, cleanText) {
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// Every section of the original text that has not been captured in a "part"
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// is filled with "text" parts, dummy objects with start/end but no extra
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// metadata.
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const allParts = textParts
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.sort(sortParts) // Sort all parts identified based on their position in the original text
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.concat(fill(textParts, cleanText))
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.sort(sortParts) // Sort them again after filling in unstyled text
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.reduce((prev, curr) => {
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const intersection = prev.some((p) => anyIntersection(p, curr));
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if (intersection) {
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return prev;
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}
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return prev.concat([curr]);
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}, []);
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// Distribute the style fragments within the text parts
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return allParts.map((textPart) => {
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textPart.fragments = styleFragments
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.filter((fragment) => anyIntersection(textPart, fragment))
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.map((fragment) => assign(textPart, fragment));
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return textPart;
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});
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}
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module.exports = merge;
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