transform() — react Function Reference

Architecture documentation for the transform() function in transform-test-gate-pragma.js from the react codebase.

Function javascript BabelCompiler Entrypoint

Entity Profile

BabelCompiler→ Entrypoint→ transform() — react Function Reference

Dependency Diagram

graph TD
  17ba2705_b3e4_6204_1a73_580da2420884["transform()"]
  808c8c36_3564_6a12_e90b_9f172bde0e83["transform-test-gate-pragma.js"]
  17ba2705_b3e4_6204_1a73_580da2420884 -->|defined in| 808c8c36_3564_6a12_e90b_9f172bde0e83
  style 17ba2705_b3e4_6204_1a73_580da2420884 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

scripts/babel/transform-test-gate-pragma.js lines 7–334

function transform(babel) {
  const {types: t} = babel;

  // A very stupid subset of pseudo-JavaScript, used to run tests conditionally
  // based on the environment.
  //
  // Input:
  //   @gate a && (b || c)
  //   test('some test', () => {/*...*/})
  //
  // Output:
  //   @gate a && (b || c)
  //   _test_gate(ctx => ctx.a && (ctx.b || ctx.c), 'some test', () => {/*...*/});
  //
  // expression     →  binary ( ( "||" | "&&" ) binary)* ;
  // binary         →  unary ( ( "==" | "!=" | "===" | "!==" ) unary )* ;
  // unary          →  "!" primary
  //                |  primary ;
  // primary        →  NAME | STRING | BOOLEAN
  //                |  "(" expression ")" ;
  function tokenize(code) {
    const tokens = [];
    let i = 0;
    while (i < code.length) {
      let char = code[i];
      // Double quoted strings
      if (char === '"') {
        let string = '';
        i++;
        do {
          if (i > code.length) {
            throw Error('Missing a closing quote');
          }
          char = code[i++];
          if (char === '"') {
            break;
          }
          string += char;
        } while (true);
        tokens.push({type: 'string', value: string});
        continue;
      }

      // Single quoted strings
      if (char === "'") {
        let string = '';
        i++;
        do {
          if (i > code.length) {
            throw Error('Missing a closing quote');
          }
          char = code[i++];
          if (char === "'") {
            break;
          }
          string += char;
        } while (true);
        tokens.push({type: 'string', value: string});
        continue;
      }

      // Whitespace
      if (/\s/.test(char)) {
        if (char === '\n') {
          return tokens;
        }
        i++;
        continue;
      }

      const next3 = code.slice(i, i + 3);
      if (next3 === '===') {
        tokens.push({type: '=='});
        i += 3;
        continue;
      }
      if (next3 === '!==') {
        tokens.push({type: '!='});
        i += 3;
        continue;
      }