JavaScript regex 测试字符串是否包含特定单词（带变量）
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JavaScript regex test if string contains specific word (with variable)
提问by Alp
I have a regex to check if a string contains a specific word. It works as expected:
我有一个正则表达式来检查字符串是否包含特定单词。它按预期工作：
/\bword\b/.test('a long text with the desired word amongst others'); // true
/\bamong\b/.test('a long text with the desired word amongst others'); // false
But i need the word which is about to be checked in a variable. Using new RegExpdoes not work properly, it always returns false:
但是我需要将要在变量中检查的单词。使用new RegExp不能正常工作，它总是返回false：
var myString = 'a long text with the desired word amongst others';
var myWord = 'word';
new RegExp('\b' + myWord + '\b').test(myString); // false
myWord = "among";
new RegExp('\b' + myWord + '\b').test(myString); // false
What is wrong here?
这里有什么问题？
回答by
var myWord = 'word';
new RegExp('\b' + myWord + '\b')
You need to double escape the \when building a regex from a string.
\从字符串构建正则表达式时，您需要双重转义。
This is because \begins an escape sequence in a string literal, so it never makes it to the regex. By doing \\, you're including a literal '\'character in the string, which makes the regex /\bword\b/.
这是因为\在字符串文字中开始一个转义序列，所以它永远不会进入正则表达式。通过这样做\\，您'\'在字符串中包含了一个文字字符，这使得正则表达式/\bword\b/.
