javascript - 是否有允许正则表达式的JavaScript的String.indexOf（）版本？(Is there a version of JavaScript's String.indexOf() that allows for regular expressions?)

Question

In javascript, is there an equivalent of String.indexOf() that takes a regular expression instead of a string for the first first parameter while still allowing a second parameter ?(在javascript中，是否有一个等效的String.indexOf（）为第一个第一个参数采用正则表达式而不是字符串，同时仍然允许第二个参数？)

I need to do something like(我需要做点什么)

str.indexOf(/[abc]/ , i);

and(和)

str.lastIndexOf(/[abc]/ , i);

While String.search() takes a regexp as a parameter it does not allow me to specify a second argument!(虽然String.search（）将regexp作为参数，但它不允许我指定第二个参数！)

Edit:(编辑：)

This turned out to be harder than I originally thought so I wrote a small test function to test all the provided solutions... it assumes regexIndexOf and regexLastIndexOf have been added to the String object.(事实证明这比我原先想象的要难，所以我编写了一个小测试函数来测试所有提供的解决方案......它假设regexIndexOf和regexLastIndexOf已被添加到String对象中。)

function test (str) {
    var i = str.length +2;
    while (i--) {
        if (str.indexOf('a',i) != str.regexIndexOf(/a/,i)) 
            alert (['failed regexIndexOf ' , str,i , str.indexOf('a',i) , str.regexIndexOf(/a/,i)]) ;
        if (str.lastIndexOf('a',i) != str.regexLastIndexOf(/a/,i) ) 
            alert (['failed regexLastIndexOf ' , str,i,str.lastIndexOf('a',i) , str.regexLastIndexOf(/a/,i)]) ;
    }
}

and I am testing as follow to make sure that at least for one character regexp, the result is the same as if we used indexOf(我正在测试如下以确保至少对于一个字符regexp，结果与我们使用indexOf时相同)

//Look for the a among the xes(//在xes中查找a)

test('xxx');(试验（ 'XXX'）;)
test('axx');(试验（ 'AXX'）;)
test('xax');(试验（ 'XAX'）;)
test('xxa');(试验（ 'XXA'）;)
test('axa');(试验（ 'AXA'）;)
test('xaa');(试验（ '的Xaa'）;)
test('aax');(试验（ 'AAX'）;)
test('aaa');(试验（ 'AAA'）;)   ask by Pat translate from so

Answer 1

Instances of the String constructor have a .search() method which accepts a RegExp and returns the index of the first match.(String构造函数的实例有一个.search()方法 ，它接受一个RegExp并返回第一个匹配的索引。)

To start the search from a particular position (faking the second parameter of .indexOf() ) you can slice off the first i characters:(要开始从特定位置的搜索（伪造的第二个参数.indexOf()则可以slice断第一i字符：)

str.slice(i).search(/re/)

But this will get the index in the shorter string (after the first part was sliced off) so you'll want to then add the length of the chopped off part ( i ) to the returned index if it wasn't -1 .(但是这将使索引处于较短的字符串中（在第一部分被切掉之后），因此如果不是-1 ，您将需要将截断的部分（ i ）的长度添加到返回的索引中。)

This will give you the index in the original string:(这将为您提供原始字符串中的索引：)

function regexIndexOf(text, re, i) {
    var indexInSuffix = text.slice(i).search(re);
    return indexInSuffix < 0 ? indexInSuffix : indexInSuffix + i;
}