将用户输入字符串转换为正则表达式

我正在用HTML和JavaScript设计一个正则表达式测试器。用户将输入一个正则表达式，一个字符串，并通过单选按钮选择他们想要测试的函数(例如搜索，匹配，替换等)，当该函数以指定的参数运行时，程序将显示结果。自然会有额外的文本框用于替换额外的参数等等。

My problem is getting the string from the user and turning it into a regular expression. If I say that they don't need to have //'s around the regex they enter, then they can't set flags, like g and i. So they have to have the //'s around the expression, but how can I convert that string to a regex? It can't be a literal since its a string, and I can't pass it to the RegExp constructor since its not a string without the //'s. Is there any other way to make a user input string into a regex? Will I have to parse the string and flags of the regex with the //'s then construct it another way? Should I have them enter a string, and then enter the flags separately?

当前回答

var flags = inputstring.replace(/.*\/([gimy]*)$/, '$1');
var pattern = inputstring.replace(new RegExp('^/(.*?)/'+flags+'$'), '$1');
var regex = new RegExp(pattern, flags);

var match = inputstring.match(new RegExp('^/(.*?)/([gimy]*)$'));
// sanity check here
var regex = new RegExp(match[1], match[2]);

2009-05-17 14:34:54

其他回答

你可以使用复选框来请求标志，然后做这样的事情:

var userInput = formInput;
var flags = '';
if(formGlobalCheckboxChecked) flags += 'g';
if(formCaseICheckboxChecked) flags += 'i';
var reg = new RegExp(userInput, flags);

2009-05-17 14:29:03

安全了，但也不安全。(一个不能访问任何其他上下文的函数版本会很好。)

const regexp = Function('return ' + string)()

2022-04-28 09:20:54

在我的例子中，用户输入有时被分隔符包围，有时没有。所以我又加了一个案例。

var regParts = inputstring.match(/^\/(.*?)\/([gim]*)$/);
if (regParts) {
    // the parsed pattern had delimiters and modifiers. handle them. 
    var regexp = new RegExp(regParts[1], regParts[2]);
} else {
    // we got pattern string without delimiters
    var regexp = new RegExp(inputstring);
}

2014-03-31 14:15:20

使用JavaScript的RegExp对象构造函数。

var re = new RegExp("\\w+");
re.test("hello");

可以将标志作为第二个字符串参数传递给构造函数。详细信息请参见文档。

2009-05-17 14:24:36

使用RegExp对象构造函数从字符串创建正则表达式:

var re = new RegExp("a|b", "i");
// same as
var re = /a|b/i;

2009-05-17 14:26:43

将用户输入字符串转换为正则表达式

推荐文章

最新文章

标签