front_end/testing/SourceMapEncoder.test.ts

// Copyright 2021 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import * as SourceMapEncoder from './SourceMapEncoder.js';

describe('SourceMapEncoder', () => {
  it('translates numbers to Base64 VLQ correctly', () => {
    assert.strictEqual(SourceMapEncoder.encodeVlq(0), 'A');
    assert.strictEqual(SourceMapEncoder.encodeVlq(-2), 'F');
    assert.strictEqual(SourceMapEncoder.encodeVlq(41), 'yC');
    assert.strictEqual(SourceMapEncoder.encodeVlq(-25), 'zB');
  });

  it('translates number lists correctly', () => {
    // Let us test the cases we care about in source maps.

    // Encoding of column-only mapping.
    assert.strictEqual('A', SourceMapEncoder.encodeVlqList([0]));
    assert.strictEqual('oG', SourceMapEncoder.encodeVlqList([100]));

    // Encoding of column => source:line:column mapping.
    assert.strictEqual('w+BoGUwM', SourceMapEncoder.encodeVlqList([1000, 100, 10, 200]));
    assert.strictEqual('DFHJ', SourceMapEncoder.encodeVlqList([-1, -2, -3, -4]));

    // Encoding of column => source:line:column@name mapping.
    assert.strictEqual('CEGIK', SourceMapEncoder.encodeVlqList([1, 2, 3, 4, 5]));
    assert.strictEqual('qGsGuGwGyG', SourceMapEncoder.encodeVlqList([101, 102, 103, 104, 105]));
  });

  it('can encode trivial source maps correctly', () => {
    // Test trivial cases.
    assert.deepEqual(
        {
          sources: [],
          names: [],
          mappings: 'A',
          version: 3,
        },
        SourceMapEncoder.encodeSourceMap(['0:0']));

    assert.deepEqual(
        {
          sources: ['a.js'],
          names: [],
          mappings: 'AAAA',
          version: 3,
        },
        SourceMapEncoder.encodeSourceMap(['0:0 => a.js:0:0']));

    assert.deepEqual(
        {
          sources: ['a.js'],
          names: ['b'],
          mappings: 'AAAAA',
          version: 3,
        },
        SourceMapEncoder.encodeSourceMap(['0:0 => a.js:0:0@b']));
  });

  it('can encode multiple lines correctly', () => {
    // Next line encoding.
    assert.strictEqual('AAAA;AACA', SourceMapEncoder.encodeSourceMap(['0:0 => a.js:0:0', '1:0 => a.js:1:0']).mappings);
    assert.strictEqual('A;A', SourceMapEncoder.encodeSourceMap(['0:0', '1:0']).mappings);

    // Skipping lines.
    assert.strictEqual(';A;;;A', SourceMapEncoder.encodeSourceMap(['1:0', '4:0']).mappings);
    assert.strictEqual(
        ';AACA;;;AAEA', SourceMapEncoder.encodeSourceMap(['1:0 => a.js:1:0', '4:0 => a.js:3:0']).mappings);
  });

  it('can encode relative offset mappings correctly', () => {
    // Relative columns.
    assert.strictEqual(
        'AAAA,EAAI,IAAD',
        SourceMapEncoder.encodeSourceMap(['0:0 => a.js:0:0', '0:2 => a.js:0:4', '0:6 => a.js:0:3']).mappings);

    // Reset after new line.
    assert.strictEqual(
        'AAAA,EAAC;MAAE',
        SourceMapEncoder.encodeSourceMap(['0:0 => a.js:0:0', '0:2 => a.js:0:1', '1:6 => a.js:0:3']).mappings);

    // Relative source, source line and source column.
    assert.deepEqual(
        {
          sources: ['a.js', 'b.js', 'c.js'],
          names: [],
          mappings: 'CACC;CCEC;CCFC;CDAH',
          version: 3,
        },
        SourceMapEncoder.encodeSourceMap(['0:1 => a.js:1:1', '1:1 => b.js:3:2', '2:1 => c.js:1:3', '3:1 => b.js:1:0']));
  });

  it('can encode names correctly', () => {
    assert.deepEqual(
        {
          sources: ['a.js'],
          names: ['a', 'b', 'c'],
          mappings: 'AAAAA;AACAC;AACAC;AACAF',
          version: 3,
        },
        SourceMapEncoder.encodeSourceMap(
            ['0:0 => a.js:0:0@a', '1:0 => a.js:1:0@b', '2:0 => a.js:2:0@c', '3:0 => a.js:3:0@a']));
  });

  it('can encode small realistic samples correctly', () => {
    assert.deepEqual(
        {
          sources: ['example.js'],
          names: ['a', 'b', 'c', 'd'],
          mappings: 'AAASA,QAAAA,IAAG,CAACC,CAAD,CAAaC,CAAb,CACZ,CACI,MAAOD,EAAP,CAAoBC,CADxB,CAIA,IAAIC,OAAS;A',
          version: 3,
        },
        SourceMapEncoder.encodeSourceMap([
          // clang-format off
          '0:0 => example.js:0:9@a',
          '0:8 => example.js:0:9@a',
          '0:12 => example.js:0:12',
          '0:13 => example.js:0:13@b',
          '0:14 => example.js:0:12',
          '0:15 => example.js:0:25@c',
          '0:16 => example.js:0:12',
          '0:17 => example.js:1:0',
          '0:18 => example.js:2:4',
          '0:24 => example.js:2:11@b',
          '0:26 => example.js:2:4',
          '0:27 => example.js:2:24@c',
          '0:28 => example.js:1:0',
          '0:29 => example.js:5:0',
          '0:33 => example.js:5:4@d',
          '0:40 => example.js:5:13',
          '1:0',
          // clang-format on
        ]));

    assert.deepEqual(
        {
          sources: ['sourcemap-stepping-source.js'],
          names: [],
          mappings:
              'AAAA,oCAAoC;;AAEpC;GACG;GAAA;GAAA;GACA;GAAA;GAAA;GACA;GAAA;GAAA;;GAEA;AACH;;AAEA;GACG;GACA;GACA;;GAEA;AACH',
          version: 3,
        },
        SourceMapEncoder.encodeSourceMap([
          // clang-format off
        '0:0 => sourcemap-stepping-source.js:0:0',
        '0:36 => sourcemap-stepping-source.js:0:36',
        '2:0 => sourcemap-stepping-source.js:2:0',
        '3:3 => sourcemap-stepping-source.js:3:3',
        '4:3 => sourcemap-stepping-source.js:3:3',
        '5:3 => sourcemap-stepping-source.js:3:3',
        '6:3 => sourcemap-stepping-source.js:4:3',
        '7:3 => sourcemap-stepping-source.js:4:3',
        '8:3 => sourcemap-stepping-source.js:4:3',
        '9:3 => sourcemap-stepping-source.js:5:3',
        '10:3 => sourcemap-stepping-source.js:5:3',
        '11:3 => sourcemap-stepping-source.js:5:3',
        '13:3 => sourcemap-stepping-source.js:7:3',
        '14:0 => sourcemap-stepping-source.js:8:0',
        '16:0 => sourcemap-stepping-source.js:10:0',
        '17:3 => sourcemap-stepping-source.js:11:3',
        '18:3 => sourcemap-stepping-source.js:12:3',
        '19:3 => sourcemap-stepping-source.js:13:3',
        '21:3 => sourcemap-stepping-source.js:15:3',
        '22:0 => sourcemap-stepping-source.js:16:0',
          // clang-format on
        ]));
  });
});