lib/index.esm.js
function (key) {
        if (!_isObject(key)) return false;
        var data = getWeak(key);
        if (data === true) return uncaughtFrozenStore(_validateCollection(this, NAME))['delete'](key);
        return data && _has(data, this._i) && delete data[this._i];
      }
function (key) {
        if (!_isObject(key)) return false;
        var data = getWeak(key);
        if (data === true) return uncaughtFrozenStore(_validateCollection(this, NAME))['delete'](key);
        return data && _has(data, this._i) && delete data[this._i];
      }
function ( key ) { if ( ! _isObject ( key ) ) return false ; var data = getWeak ( key ) ; if ( data === true ) return uncaughtFrozenStore ( _validateCollection ( this , NAME ) ) [ 'delete' ] ( key ) ; return data && _has ( data , this . _i ) && delete data [ this . _i ] ; }
23.3.3.2 WeakMap.prototype.delete(key) 23.4.3.3 WeakSet.prototype.delete(value)
23 . 3 . 3 . 2 WeakMap . prototype . delete ( key ) 23 . 4 . 3 . 3 WeakSet . prototype . delete ( value )