computeMemoizationInputs() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PruneNonEscapingScopes.ts lines 423–858

  computeMemoizationInputs(
    value: ReactiveValue,
    lvalue: Place | null,
  ): {
    // can optionally return a custom set of lvalues per instruction
    lvalues: Array<LValueMemoization>;
    rvalues: Array<Place>;
  } {
    const env = this.env;
    const options = this.options;

    switch (value.kind) {
      case 'ConditionalExpression': {
        return {
          // Only need to memoize if the rvalues are memoized
          lvalues:
            lvalue !== null
              ? [{place: lvalue, level: MemoizationLevel.Conditional}]
              : [],
          rvalues: [
            // Conditionals do not alias their test value.
            ...this.computeMemoizationInputs(value.consequent, null).rvalues,
            ...this.computeMemoizationInputs(value.alternate, null).rvalues,
          ],
        };
      }
      case 'LogicalExpression': {
        return {
          // Only need to memoize if the rvalues are memoized
          lvalues:
            lvalue !== null
              ? [{place: lvalue, level: MemoizationLevel.Conditional}]
              : [],
          rvalues: [
            ...this.computeMemoizationInputs(value.left, null).rvalues,
            ...this.computeMemoizationInputs(value.right, null).rvalues,
          ],
        };
      }
      case 'SequenceExpression': {
        for (const instr of value.instructions) {
          this.visitValueForMemoization(instr.id, instr.value, instr.lvalue);
        }
        return {
          // Only need to memoize if the rvalues are memoized
          lvalues:
            lvalue !== null
              ? [{place: lvalue, level: MemoizationLevel.Conditional}]
              : [],
          /*
           * Only the final value of the sequence is a true rvalue:
           * values from the sequence's instructions are evaluated
           * as separate nodes
           */
          rvalues: this.computeMemoizationInputs(value.value, null).rvalues,
        };
      }
      case 'JsxExpression': {
        const operands: Array<Place> = [];
        if (value.tag.kind === 'Identifier') {
          operands.push(value.tag);
        }
        for (const prop of value.props) {
          if (prop.kind === 'JsxAttribute') {
            operands.push(prop.place);
          } else {
            operands.push(prop.argument);
          }
        }
        if (value.children !== null) {
          for (const child of value.children) {
            operands.push(child);
          }
        }
        const level = options.memoizeJsxElements
          ? MemoizationLevel.Memoized
          : MemoizationLevel.Unmemoized;
        return {
          /*
           * JSX elements themselves are not memoized unless forced to
           * avoid breaking downstream memoization