merge() — react Function Reference

Architecture documentation for the merge() function in DeriveMinimalDependenciesHIR.ts from the react codebase.

Function typescript MIRInfrastructure HIR calls 3 called by 2

Entity Profile

MIRInfrastructure→ HIR→ merge() — react Function Reference

Dependency Diagram

graph TD
  fde4af26_13b5_6adc_3afe_f724f66c9a93["merge()"]
  686094a4_f90a_6b2e_949a_aa03f03b5c66["DeriveMinimalDependenciesHIR.ts"]
  fde4af26_13b5_6adc_3afe_f724f66c9a93 -->|defined in| 686094a4_f90a_6b2e_949a_aa03f03b5c66
  61f036d0_eb91_7e31_154e_acb3c7c8f23c["addDependency()"]
  61f036d0_eb91_7e31_154e_acb3c7c8f23c -->|calls| fde4af26_13b5_6adc_3afe_f724f66c9a93
  38ab4c9b_814c_2f1c_3661_630e72f557fd["makeOrMergeProperty()"]
  38ab4c9b_814c_2f1c_3661_630e72f557fd -->|calls| fde4af26_13b5_6adc_3afe_f724f66c9a93
  7930cad6_ab99_ae3b_5cac_03042fe5727b["merge()"]
  fde4af26_13b5_6adc_3afe_f724f66c9a93 -->|calls| 7930cad6_ab99_ae3b_5cac_03042fe5727b
  313f0afe_6db1_bf05_f22c_502906b24f00["isOptional()"]
  fde4af26_13b5_6adc_3afe_f724f66c9a93 -->|calls| 313f0afe_6db1_bf05_f22c_502906b24f00
  6a38958d_320b_9a16_a7b1_b21a4633841c["isDependency()"]
  fde4af26_13b5_6adc_3afe_f724f66c9a93 -->|calls| 6a38958d_320b_9a16_a7b1_b21a4633841c
  style fde4af26_13b5_6adc_3afe_f724f66c9a93 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

compiler/packages/babel-plugin-react-compiler/src/HIR/DeriveMinimalDependenciesHIR.ts lines 275–304

function merge(
  access1: PropertyAccessType,
  access2: PropertyAccessType,
): PropertyAccessType {
  const resultIsUnconditional = !(isOptional(access1) && isOptional(access2));
  const resultIsDependency = isDependency(access1) || isDependency(access2);

  /*
   * Straightforward merge.
   * This can be represented as bitwise OR, but is written out for readability
   *
   * Observe that `UnconditionalAccess | ConditionalDependency` produces an
   * unconditionally accessed conditional dependency. We currently use these
   * as we use unconditional dependencies. (i.e. to codegen change variables)
   */
  if (resultIsUnconditional) {
    if (resultIsDependency) {
      return PropertyAccessType.UnconditionalDependency;
    } else {
      return PropertyAccessType.UnconditionalAccess;
    }
  } else {
    // result is optional
    if (resultIsDependency) {
      return PropertyAccessType.OptionalDependency;
    } else {
      return PropertyAccessType.OptionalAccess;
    }
  }
}