computeSignatureForInstruction() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Inference/InferMutationAliasingEffects.ts lines 1724–2305

function computeSignatureForInstruction(
  context: Context,
  env: Environment,
  instr: Instruction,
): InstructionSignature {
  const {lvalue, value} = instr;
  const effects: Array<AliasingEffect> = [];
  switch (value.kind) {
    case 'ArrayExpression': {
      effects.push({
        kind: 'Create',
        into: lvalue,
        value: ValueKind.Mutable,
        reason: ValueReason.Other,
      });
      // All elements are captured into part of the output value
      for (const element of value.elements) {
        if (element.kind === 'Identifier') {
          effects.push({
            kind: 'Capture',
            from: element,
            into: lvalue,
          });
        } else if (element.kind === 'Spread') {
          const mutateIterator = conditionallyMutateIterator(element.place);
          if (mutateIterator != null) {
            effects.push(mutateIterator);
          }
          effects.push({
            kind: 'Capture',
            from: element.place,
            into: lvalue,
          });
        } else {
          continue;
        }
      }
      break;
    }
    case 'ObjectExpression': {
      effects.push({
        kind: 'Create',
        into: lvalue,
        value: ValueKind.Mutable,
        reason: ValueReason.Other,
      });
      for (const property of value.properties) {
        if (property.kind === 'ObjectProperty') {
          effects.push({
            kind: 'Capture',
            from: property.place,
            into: lvalue,
          });
        } else {
          effects.push({
            kind: 'Capture',
            from: property.place,
            into: lvalue,
          });
        }
      }
      break;
    }
    case 'Await': {
      effects.push({
        kind: 'Create',
        into: lvalue,
        value: ValueKind.Mutable,
        reason: ValueReason.Other,
      });
      // Potentially mutates the receiver (awaiting it changes its state and can run side effects)
      effects.push({kind: 'MutateTransitiveConditionally', value: value.value});
      /**
       * Data from the promise may be returned into the result, but await does not directly return
       * the promise itself
       */
      effects.push({
        kind: 'Capture',
        from: value.value,
        into: lvalue,
      });