codegenReactiveScope() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/CodegenReactiveFunction.ts lines 601–935

function codegenReactiveScope(
  cx: Context,
  statements: Array<t.Statement>,
  scope: ReactiveScope,
  block: ReactiveBlock,
): void {
  const cacheStoreStatements: Array<t.Statement> = [];
  const cacheLoadStatements: Array<t.Statement> = [];
  const cacheLoads: Array<{
    name: t.Identifier;
    index: number;
    value: t.Expression;
  }> = [];
  const changeExpressions: Array<t.Expression> = [];
  const changeExpressionComments: Array<string> = [];
  const outputComments: Array<string> = [];

  for (const dep of [...scope.dependencies].sort(compareScopeDependency)) {
    const index = cx.nextCacheIndex;
    changeExpressionComments.push(printDependencyComment(dep));
    const comparison = t.binaryExpression(
      '!==',
      t.memberExpression(
        t.identifier(cx.synthesizeName('$')),
        t.numericLiteral(index),
        true,
      ),
      codegenDependency(cx, dep),
    );

    if (cx.env.config.enableChangeVariableCodegen) {
      const changeIdentifier = t.identifier(cx.synthesizeName(`c_${index}`));
      statements.push(
        t.variableDeclaration('const', [
          t.variableDeclarator(changeIdentifier, comparison),
        ]),
      );
      changeExpressions.push(changeIdentifier);
    } else {
      changeExpressions.push(comparison);
    }
    /*
     * Adding directly to cacheStoreStatements rather than cacheLoads, because there
     * is no corresponding cacheLoadStatement for dependencies
     */
    cacheStoreStatements.push(
      t.expressionStatement(
        t.assignmentExpression(
          '=',
          t.memberExpression(
            t.identifier(cx.synthesizeName('$')),
            t.numericLiteral(index),
            true,
          ),
          codegenDependency(cx, dep),
        ),
      ),
    );
  }
  let firstOutputIndex: number | null = null;

  for (const [, {identifier}] of [...scope.declarations].sort(([, a], [, b]) =>
    compareScopeDeclaration(a, b),
  )) {
    const index = cx.nextCacheIndex;
    if (firstOutputIndex === null) {
      firstOutputIndex = index;
    }

    CompilerError.invariant(identifier.name != null, {
      reason: `Expected scope declaration identifier to be named`,
      description: `Declaration \`${printIdentifier(
        identifier,
      )}\` is unnamed in scope @${scope.id}`,
      loc: GeneratedSource,
    });

    const name = convertIdentifier(identifier);
    outputComments.push(name.name);
    if (!cx.hasDeclared(identifier)) {
      statements.push(