substitute() — react Function Reference

Architecture documentation for the substitute() function in TypeUtils.ts from the react codebase.

Function typescript BabelCompiler Validation calls 3

Entity Profile

BabelCompiler→ Validation→ substitute() — react Function Reference

Dependency Diagram

graph TD
  5b033808_ef9f_1c72_998b_14de0ddb4423["substitute()"]
  1fccc28d_09ce_cbd9_cc1b_5224a1b90f93["TypeUtils.ts"]
  5b033808_ef9f_1c72_998b_14de0ddb4423 -->|defined in| 1fccc28d_09ce_cbd9_cc1b_5224a1b90f93
  d530521b_d20e_08a8_4bec_1170867678c4["mapType()"]
  5b033808_ef9f_1c72_998b_14de0ddb4423 -->|calls| d530521b_d20e_08a8_4bec_1170867678c4
  38999144_d544_edc0_6efe_18d9bf834ada["printType()"]
  5b033808_ef9f_1c72_998b_14de0ddb4423 -->|calls| 38999144_d544_edc0_6efe_18d9bf834ada
  c0b647d9_982f_2dc6_de63_c350aa5665d4["printConcrete()"]
  5b033808_ef9f_1c72_998b_14de0ddb4423 -->|calls| c0b647d9_982f_2dc6_de63_c350aa5665d4
  style 5b033808_ef9f_1c72_998b_14de0ddb4423 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

compiler/packages/babel-plugin-react-compiler/src/Flood/TypeUtils.ts lines 14–55

export function substitute(
  type: ConcreteType<ResolvedType>,
  typeParameters: Array<TypeParameter<ResolvedType>>,
  typeArguments: Array<ResolvedType>,
): ResolvedType {
  const substMap = new Map<TypeParameterId, ResolvedType>();
  for (let i = 0; i < typeParameters.length; i++) {
    // TODO: Length checks to make sure type params match up with args
    const typeParameter = typeParameters[i];
    const typeArgument = typeArguments[i];
    substMap.set(typeParameter.id, typeArgument);
  }
  const substitutionFunction = (t: ResolvedType): ResolvedType => {
    // TODO: We really want a stateful mapper or visitor here so that we can model nested polymorphic types
    if (t.type.kind === 'Generic' && substMap.has(t.type.id)) {
      const substitutedType = substMap.get(t.type.id)!;
      return substitutedType;
    }

    return {
      kind: 'Concrete',
      type: mapType(substitutionFunction, t.type),
      platform: t.platform,
    };
  };

  const substituted = mapType(substitutionFunction, type);

  if (DEBUG) {
    let substs = '';
    for (let i = 0; i < typeParameters.length; i++) {
      const typeParameter = typeParameters[i];
      const typeArgument = typeArguments[i];
      substs += `[${typeParameter.name}${typeParameter.id} := ${printType(typeArgument)}]`;
    }
    console.log(
      `${printConcrete(type, printType)}${substs} = ${printConcrete(substituted, printType)}`,
    );
  }

  return {kind: 'Concrete', type: substituted, platform: /* TODO */ 'shared'};
}