validateNoImpureFunctionsInRender() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidateNoImpureFunctionsInRender.ts lines 23–59

export function validateNoImpureFunctionsInRender(
  fn: HIRFunction,
): Result<void, CompilerError> {
  const errors = new CompilerError();
  for (const [, block] of fn.body.blocks) {
    for (const instr of block.instructions) {
      const value = instr.value;
      if (value.kind === 'MethodCall' || value.kind == 'CallExpression') {
        const callee =
          value.kind === 'MethodCall' ? value.property : value.callee;
        const signature = getFunctionCallSignature(
          fn.env,
          callee.identifier.type,
        );
        if (signature != null && signature.impure === true) {
          errors.pushDiagnostic(
            CompilerDiagnostic.create({
              category: ErrorCategory.Purity,
              reason: 'Cannot call impure function during render',
              description:
                (signature.canonicalName != null
                  ? `\`${signature.canonicalName}\` is an impure function. `
                  : '') +
                'Calling an impure function can produce unstable results that update unpredictably when the component happens to re-render. (https://react.dev/reference/rules/components-and-hooks-must-be-pure#components-and-hooks-must-be-idempotent)',
              suggestions: null,
            }).withDetails({
              kind: 'error',
              loc: callee.loc,
              message: 'Cannot call impure function',
            }),
          );
        }
      }
    }
  }
  return errors.asResult();
}