类型判断
export const objectToString = Object.prototype.toString;
export const toTypeString = (value: unknown): string =>
objectToString.call(value);
export const toRawType = (value: unknown): string =>
toTypeString(value).slice(8, -1);
export const isArray = Array.isArray;
export const isMap = (val: unknown): val is Map<any, any> =>
toTypeString(val) === '[object Map]';
export const isSet = (val: unknown): val is Set<any> =>
toTypeString(val) === '[object Set]';
export const isDate = (val: unknown): val is Date =>
toTypeString(val) === '[object Date]';
export const isFunction = (val: unknown): val is Function =>
typeof val === 'function';
export const isString = (val: unknown): val is string =>
typeof val === 'string';
export const isSymbol = (val: unknown): val is symbol =>
typeof val === 'symbol';
export const isObject = (val: unknown): val is Record<any, any> =>
val !== null && typeof val === 'object';
export const isPromise = <T = any>(val: unknown): val is Promise<T> =>
isObject(val) && isFunction(val.then) && isFunction(val.catch);
export const isPlainObject = (val: unknown): val is object =>
toTypeString(val) === '[object Object]';
export const isIntegerKey = (key: unknown) =>
isString(key) &&
key !== 'NaN' &&
key[0] !== '-' &&
`${parseInt(key, 10)}` === key;