isEmpty [is 空的]

如果A值是一个空对象，集合，则返回true。

检查提供的值是 null 或者如果它 length 等于 0.

typescript

const isEmpty = (val: any) => val == null || !(Object.keys(val) || val).length;

// If typescript compiler is yelling because of the type `any`
const isEmpty = (val: Record<string, unknown> | null | undefined) =>
  val == null || !(Object.keys(val) || val).length;

typescript

isEmpty([]); // true
isEmpty({}); // true
isEmpty(""); // true
isEmpty([1, 2]); // false
isEmpty({ a: 1, b: 2 }); // false
isEmpty("text"); // false
isEmpty(123); // true - type is not considered a collection
isEmpty(true); // true - type is not considered a collection