File: index.js

package info (click to toggle)
node-babel 6.26.0%2Brepack-3~bpo10%2B1
  • links: PTS, VCS
  • area: main
  • in suites: buster-backports
  • size: 28,708 kB
  • sloc: sh: 170; makefile: 76
file content (148 lines) | stat: -rw-r--r-- 3,878 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
import detectIndent from "detect-indent";
import SourceMap from "./source-map";
import * as messages from "babel-messages";
import Printer from "./printer";
import type { Format } from "./printer";

/**
 * Babel's code generator, turns an ast into code, maintaining sourcemaps,
 * user preferences, and valid output.
 */

class Generator extends Printer {
  constructor(ast, opts = {}, code) {
    const tokens = ast.tokens || [];
    const format = normalizeOptions(code, opts, tokens);
    const map = opts.sourceMaps ? new SourceMap(opts, code) : null;
    super(format, map, tokens);

    this.ast = ast;
  }

  ast: Object;

  /**
   * Generate code and sourcemap from ast.
   *
   * Appends comments that weren't attached to any node to the end of the generated output.
   */

  generate() {
    return super.generate(this.ast);
  }
}

/**
 * Normalize generator options, setting defaults.
 *
 * - Detects code indentation.
 * - If `opts.compact = "auto"` and the code is over 500KB, `compact` will be set to `true`.
 */

function normalizeOptions(code, opts, tokens): Format {
  let style = "  ";
  if (code && typeof code === "string") {
    const indent = detectIndent(code).indent;
    if (indent && indent !== " ") style = indent;
  }

  const format = {
    auxiliaryCommentBefore: opts.auxiliaryCommentBefore,
    auxiliaryCommentAfter: opts.auxiliaryCommentAfter,
    shouldPrintComment: opts.shouldPrintComment,
    retainLines: opts.retainLines,
    retainFunctionParens: opts.retainFunctionParens,
    comments: opts.comments == null || opts.comments,
    compact: opts.compact,
    minified: opts.minified,
    concise: opts.concise,
    quotes: opts.quotes || findCommonStringDelimiter(code, tokens),
    jsonCompatibleStrings: opts.jsonCompatibleStrings,
    indent: {
      adjustMultilineComment: true,
      style: style,
      base: 0
    },
    flowCommaSeparator: opts.flowCommaSeparator,
  };

  if (format.minified) {
    format.compact = true;

    format.shouldPrintComment = format.shouldPrintComment || (() => format.comments);
  } else {
    format.shouldPrintComment = format.shouldPrintComment || ((value) => format.comments ||
      (value.indexOf("@license") >= 0 || value.indexOf("@preserve") >= 0));
  }

  if (format.compact === "auto") {
    format.compact = code.length > 500000; // 500KB

    if (format.compact) {
      console.error("[BABEL] " + messages.get("codeGeneratorDeopt", opts.filename, "500KB"));
    }
  }

  if (format.compact) {
    format.indent.adjustMultilineComment = false;
  }

  return format;
}

/**
 * Determine if input code uses more single or double quotes.
 */
function findCommonStringDelimiter(code, tokens) {
  const DEFAULT_STRING_DELIMITER = "double";
  if (!code) {
    return DEFAULT_STRING_DELIMITER;
  }

  const occurrences = {
    single: 0,
    double: 0
  };

  let checked = 0;

  for (let i = 0; i < tokens.length; i++) {
    const token = tokens[i];
    if (token.type.label !== "string") continue;

    const raw = code.slice(token.start, token.end);
    if (raw[0] === "'") {
      occurrences.single++;
    } else {
      occurrences.double++;
    }

    checked++;
    if (checked >= 3) break;
  }
  if (occurrences.single > occurrences.double) {
    return "single";
  } else {
    return "double";
  }
}

/**
 * We originally exported the Generator class above, but to make it extra clear that it is a private API,
 * we have moved that to an internal class instance and simplified the interface to the two public methods
 * that we wish to support.
 */

export class CodeGenerator {
  constructor(ast, opts, code) {
    this._generator = new Generator(ast, opts, code);
  }
  generate() {
    return this._generator.generate();
  }
}

export default function (ast: Object, opts: Object, code: string): Object {
  const gen = new Generator(ast, opts, code);
  return gen.generate();
}