React 捕获的值

一、作用

二、在 Fiber 上创建捕获值

备注

• getStackByFiberInDevAndProd() 由 ReactFiberComponentStack#getStackByFiberInDevAndProd 实现

export function createCapturedValueAtFiber<T>(
  value: T,
  source: Fiber,
): CapturedValue<T> {
  // If the value is an error, call this function immediately after it is thrown
  // so the stack is accurate.
  //
  // 如果值是错误，在抛出后立即调用此函数
  // 以确保堆栈信息准确。
  if (typeof value === 'object' && value !== null) {
    const existing = CapturedStacks.get(value);
    if (existing !== undefined) {
      return existing;
    }
    const captured: CapturedValue<T> = {
      value,
      source,
      stack: getStackByFiberInDevAndProd(source),
    };
    CapturedStacks.set(value, captured);
    return captured;
  } else {
    return {
      value,
      source,
      stack: getStackByFiberInDevAndProd(source),
    };
  }
}

三、从错误创建捕获值

export function createCapturedValueFromError(
  value: Error,
  stack: null | string,
): CapturedValue<Error> {
  const captured = {
    value,
    source: null,
    stack: stack,
  };
  if (typeof stack === 'string') {
    CapturedStacks.set(value, captured);
  }
  return captured;
}

四、常量

1. 捕获的栈

const CapturedStacks: WeakMap<any, CapturedValue<any>> = new WeakMap();