javascript - jquery.trim 与 string.trim 相比

Question

jQuery trim 和原生 JavaScript trim 之间有什么区别吗？

是否有其他行为、安全、性能？

Answer 1

JavaScript .trim() 是在 ES 5.1 中定义的，不适用于 IE<9。因此，如果您已经在使用 jQuery，则可以使用性能较低的 $.trim()

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jQuery 的 $.trim() 方法:

trim: function( text ) {
    return text == null ? "" : ( text + "" ).replace( rtrim, "" );
}

rtrim 基本上就是这个 RegExp

new RegExp( "^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$", "g" )

和whitespace表示为这个组:

"[\\x20\\t\\r\\n\\f]"

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在 JavaScript (ES6)它被定义为:

21.1.3.25 String.prototype.trim ( )

This function interprets a String value as a sequence of UTF-16 encoded code points, as described in 6.1.4.

The following steps are taken: Let O be RequireObjectCoercible(this value). Let S be ToString(O). ReturnIfAbrupt(S). Let T be a String value that is a copy of S with both leading and trailing white space removed. The definition of white space is the union of WhiteSpace and LineTerminator. When determining whether a Unicode code point is in Unicode general category “Zs”, code unit sequences are interpreted as UTF-16 encoded code point sequences as specified in 6.1.4. Return T. NOTE The trim function is intentionally generic; it does not require that its this value be a String object. Therefore, it can be transferred to other kinds of objects for use as a method.

所以先不说JS的.trim()对浏览器厂商的实现，重点很明确:
从字符串的开头和结尾删除换行符或空格的任何表示。