作用

仅在开发时检查评估可用性

export function checkEvalAvailabilityOnceDev(): void {
  if (__DEV__) {
    if (!hasConfirmedEval) {
      hasConfirmedEval = true;
      try {
        (0, eval)('null');
      } catch {
        console.error(
          'eval() is not supported in this environment. ' +
            'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, ' +
            'or if `eval` was patched by other means. ' +
            'React requires eval() in development mode for various debugging features ' +
            'like reconstructing callstacks from a different environment.\n' +
            'React will never use eval() in production mode',
        );
      }
    }
  } else {
    // These errors should never make it into a build so we don't need to encode them in codes.json
    // 这些错误绝不应该出现在构建中，所以我们不需要在 codes.json 中对它们进行编码
    throw new Error(
      'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
    );
  }
}

变量

已确认评估

备注

源码中 10 行

let hasConfirmedEval = false;