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