Function plainObjectCheck

tfjs-layers/src/user_defined_metadata.ts:64–104

(x: any)

 */
// tslint:disable-next-line:no-any
export function plainObjectCheck(x: any): boolean {
  if (x === null) {
    // Note: typeof `null` is 'object', and `null` is valid in JSON.
    return true;
  } else if (typeof x === 'object') {
    if (Object.getPrototypeOf(x) === Object.prototype) {
      // `x` is a JavaScript object and its prototype is Object.
      const keys = Object.keys(x);
      for (const key of keys) {
        if (typeof key !== 'string') {
          // JSON keys must be strings.
          return false;
        }
        if (!plainObjectCheck(x[key])) {  // Recursive call.
          return false;
        }
      }
      return true;
    } else {
      // `x` is a JavaScript object but its prototype is not Object.
      if (Array.isArray(x)) {
        // `x` is a JavaScript array.
        for (const item of x) {
          if (!plainObjectCheck(item)) {  // Recursive call.
            return false;
          }
        }
        return true;
      } else {
        // `x` is a JavaScript object and its prototype is not Object,
        // and it's not an Array. I.e., it's a complex object such as
        // `Error` and `Date`.
        return false;
      }
    }
  } else {
    // `x` is not a JavaScript object or `null`.
    const xType = typeof x;
    return xType === 'string' || xType === 'number' || xType === 'boolean';
  }
}