全新的JS,所以请原谅,如果这是令人难以置信的明显.
假设我想使用映射字符串的功能f过滤字符串列表 – >布尔.这样做：
filteredList = list.filter(function(x) { return f(x); })
这失败了：
filteredList = list.filter(f)
为什么？？？
代码示例：
~/projects/node (master)$node
> var items = ["node.js","file.txt"]
undefined
> var regex = new RegExp('\\.js$')
undefined
> items.filter(regex.test)
TypeError: Method RegExp.prototype.test called on incompatible receiver undefined
at test (native)
at Array.filter (native)
at repl:1:8
at REPLServer.self.eval (repl.js:110:21)
at Interface.<anonymous> (repl.js:239:12)
at Interface.EventEmitter.emit (events.js:95:17)
at Interface._onLine (readline.js:202:10)
at Interface._line (readline.js:531:8)
at Interface._ttyWrite (readline.js:760:14)
at ReadStream.onkeypress (readline.js:99:10)
> items.filter(function(value) { return regex.test(value); } )
[ 'node.js' ]
>
