46 lines
1.2 KiB
JavaScript
46 lines
1.2 KiB
JavaScript
// alter.js
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// MIT licensed, see LICENSE file
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// Copyright (c) 2013 Olov Lassus <olov.lassus@gmail.com>
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var assert = require("assert");
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var stableSort = require("stable");
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// fragments is a list of {start: index, end: index, str: string to replace with}
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function alter(str, fragments) {
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"use strict";
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var isArray = Array.isArray || function(v) {
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return Object.prototype.toString.call(v) === "[object Array]";
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};;
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assert(typeof str === "string");
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assert(isArray(fragments));
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// stableSort isn't in-place so no need to copy array first
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var sortedFragments = stableSort(fragments, function(a, b) {
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return a.start - b.start;
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});
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var outs = [];
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var pos = 0;
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for (var i = 0; i < sortedFragments.length; i++) {
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var frag = sortedFragments[i];
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assert(pos <= frag.start);
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assert(frag.start <= frag.end);
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outs.push(str.slice(pos, frag.start));
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outs.push(frag.str);
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pos = frag.end;
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}
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if (pos < str.length) {
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outs.push(str.slice(pos));
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}
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return outs.join("");
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}
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if (typeof module !== "undefined" && typeof module.exports !== "undefined") {
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module.exports = alter;
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}
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