Javascript中字符串的第一个单词的位置

Question

I originally used indexOf to find a space but I want to find any word boundary. 我最初使用indexOf来查找空格，但我想找到任何单词边界。

Something like this, but what regex? 像这样的东西，但是什么正则表达式？

var str = "This is a sentence",
firstword = str.search("");
return word;

I want to return "This". 我想要回复“这个”。 Even in the case of a tab, period, comma, etc. 即使在制表符，句号，逗号等的情况下也是如此。

Answer 1

Something like this: 像这样的东西：

var str = "This is a sentence"; 
return str.split(/\b/)[0];

Although you would probably want to check that there was a match like this: 虽然您可能想要检查是否存在这样的匹配：

var str = "This is a sentence"; 
var matches = str.split(/\b/);
return matches.length > 0 ? matches[0] : "";

Answer 2

This splits the string at every word boundary and returns the first one: 这会在每个单词边界处拆分字符串并返回第一个字符串：

var str = "This is a sentence";
firstword = str.split(/\b/)[0];