validateLocalsNotReassignedAfterRender() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidateLocalsNotReassignedAfterRender.ts lines 23–51

export function validateLocalsNotReassignedAfterRender(fn: HIRFunction): void {
  const contextVariables = new Set<IdentifierId>();
  const reassignment = getContextReassignment(
    fn,
    contextVariables,
    false,
    false,
  );
  if (reassignment !== null) {
    const errors = new CompilerError();
    const variable =
      reassignment.identifier.name != null &&
      reassignment.identifier.name.kind === 'named'
        ? `\`${reassignment.identifier.name.value}\``
        : 'variable';
    errors.pushDiagnostic(
      CompilerDiagnostic.create({
        category: ErrorCategory.Immutability,
        reason: 'Cannot reassign variable after render completes',
        description: `Reassigning ${variable} after render has completed can cause inconsistent behavior on subsequent renders. Consider using state instead`,
      }).withDetails({
        kind: 'error',
        loc: reassignment.loc,
        message: `Cannot reassign ${variable} after render completes`,
      }),
    );
    throw errors;
  }
}