inlineJsxTransform() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Optimization/InlineJsxTransform.ts lines 66–428

export function inlineJsxTransform(
  fn: HIRFunction,
  inlineJsxTransformConfig: NonNullable<
    EnvironmentConfig['inlineJsxTransform']
  >,
): void {
  const inlinedJsxDeclarations: InlinedJsxDeclarationMap = new Map();
  /**
   * Step 1: Codegen the conditional and ReactElement object literal
   */
  for (const [_, currentBlock] of [...fn.body.blocks]) {
    let fallthroughBlockInstructions: Array<Instruction> | null = null;
    const instructionCount = currentBlock.instructions.length;
    for (let i = 0; i < instructionCount; i++) {
      const instr = currentBlock.instructions[i]!;
      // TODO: Support value blocks
      if (currentBlock.kind === 'value') {
        fn.env.logger?.logEvent(fn.env.filename, {
          kind: 'CompileDiagnostic',
          fnLoc: null,
          detail: {
            category: ErrorCategory.Todo,
            reason: 'JSX Inlining is not supported on value blocks',
            loc: instr.loc,
          },
        });
        continue;
      }
      switch (instr.value.kind) {
        case 'JsxExpression':
        case 'JsxFragment': {
          /**
           * Split into blocks for new IfTerminal:
           *   current, then, else, fallthrough
           */
          const currentBlockInstructions = currentBlock.instructions.slice(
            0,
            i,
          );
          const thenBlockInstructions = currentBlock.instructions.slice(
            i,
            i + 1,
          );
          const elseBlockInstructions: Array<Instruction> = [];
          fallthroughBlockInstructions ??= currentBlock.instructions.slice(
            i + 1,
          );

          const fallthroughBlockId = fn.env.nextBlockId;
          const fallthroughBlock: BasicBlock = {
            kind: currentBlock.kind,
            id: fallthroughBlockId,
            instructions: fallthroughBlockInstructions,
            terminal: currentBlock.terminal,
            preds: new Set(),
            phis: new Set(),
          };

          /**
           * Complete current block
           * - Add instruction for variable declaration
           * - Add instruction for LoadGlobal used by conditional
           * - End block with a new IfTerminal
           */
          const varPlace = createTemporaryPlace(fn.env, instr.value.loc);
          promoteTemporary(varPlace.identifier);
          const varLValuePlace = createTemporaryPlace(fn.env, instr.value.loc);
          const thenVarPlace = {
            ...varPlace,
            identifier: forkTemporaryIdentifier(
              fn.env.nextIdentifierId,
              varPlace.identifier,
            ),
          };
          const elseVarPlace = {
            ...varPlace,
            identifier: forkTemporaryIdentifier(
              fn.env.nextIdentifierId,
              varPlace.identifier,
            ),
          };