145 lines
3.8 KiB
JavaScript
145 lines
3.8 KiB
JavaScript
/**
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* Copyright (c) 2014, Facebook, Inc. All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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*
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*/
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'use strict';
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const chalk = require('chalk');
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const diff = require('diff');var _require =
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require('./constants.js');const NO_DIFF_MESSAGE = _require.NO_DIFF_MESSAGE;
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const DIFF_CONTEXT = 5;
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const getColor = (added, removed) =>
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added ?
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chalk.red :
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removed ? chalk.green : chalk.dim;
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const getBgColor = (added, removed) =>
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added ?
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chalk.bgRed :
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removed ? chalk.bgGreen : chalk.dim;
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const highlightTrailingWhitespace = (line, bgColor) =>
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line.replace(/\s+$/, bgColor('$&'));
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const getAnnotation = options =>
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chalk.green('- ' + (options && options.aAnnotation || 'Expected')) + '\n' +
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chalk.red('+ ' + (options && options.bAnnotation || 'Received')) + '\n\n';
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const diffLines = (a, b) => {
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let isDifferent = false;
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return {
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diff: diff.diffLines(a, b).map(part => {const
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added = part.added,removed = part.removed;
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if (part.added || part.removed) {
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isDifferent = true;
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}
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const lines = part.value.split('\n');
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const color = getColor(added, removed);
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const bgColor = getBgColor(added, removed);
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if (lines[lines.length - 1] === '') {
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lines.pop();
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}
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return lines.map(line => {
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const highlightedLine = highlightTrailingWhitespace(line, bgColor);
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const mark = color(part.added ? '+' : part.removed ? '-' : ' ');
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return mark + ' ' + color(highlightedLine) + '\n';
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}).join('');
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}).join('').trim(),
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isDifferent };
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};
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// Only show patch marks ("@@ ... @@") if the diff is big.
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// To determine this, we need to compare either the original string (a) to
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// `hunk.oldLines` or a new string to `hunk.newLines`.
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// If the `oldLinesCount` is greater than `hunk.oldLines`
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// we can be sure that at least 1 line has been "hidden".
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const shouldShowPatchMarks =
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(hunk, oldLinesCount) => oldLinesCount > hunk.oldLines;
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const createPatchMark = hunk => {
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const markOld = `-${hunk.oldStart},${hunk.oldLines}`;
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const markNew = `+${hunk.newStart},${hunk.newLines}`;
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return chalk.yellow(`@@ ${markOld} ${markNew} @@\n`);
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};
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const structuredPatch = (a, b) => {
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const options = { context: DIFF_CONTEXT };
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let isDifferent = false;
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// Make sure the strings end with a newline.
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if (!a.endsWith('\n')) {
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a += '\n';
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}
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if (!b.endsWith('\n')) {
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b += '\n';
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}
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const oldLinesCount = (a.match(/\n/g) || []).length;
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return {
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diff: diff.structuredPatch('', '', a, b, '', '', options).
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hunks.map(hunk => {
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const lines = hunk.lines.map(line => {
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const added = line[0] === '+';
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const removed = line[0] === '-';
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const color = getColor(added, removed);
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const bgColor = getBgColor(added, removed);
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const highlightedLine = highlightTrailingWhitespace(line, bgColor);
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return color(highlightedLine) + '\n';
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}).join('');
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isDifferent = true;
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return shouldShowPatchMarks(hunk, oldLinesCount) ?
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createPatchMark(hunk) + lines :
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lines;
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}).join('').trim(),
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isDifferent };
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};
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function diffStrings(a, b, options) {
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// `diff` uses the Myers LCS diff algorithm which runs in O(n+d^2) time
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// (where "d" is the edit distance) and can get very slow for large edit
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// distances. Mitigate the cost by switching to a lower-resolution diff
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// whenever linebreaks are involved.
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const result = options && options.expand === false ?
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structuredPatch(a, b) :
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diffLines(a, b);
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if (result.isDifferent) {
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return getAnnotation(options) + result.diff;
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} else {
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return NO_DIFF_MESSAGE;
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}
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}
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module.exports = diffStrings; |