one line match in JS regex

What is the JavaScript equivalent of this .NET code?

var b = Regex开发者_运维问答.IsMatch(txt, pattern);

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Here are the useful functions for working with regexes.

• exec A RegExp method that executes a search for a match in a string. It returns an array of information.
• test A RegExp method that tests for a match in a string. It returns true or false.
• match A String method that executes a search for a match in a string. It returns an array of information or null on a mismatch.
• search A String method that tests for a match in a string. It returns the index of the match, or -1 if the search fails.
• replace A String method that executes a search for a match in a string, and replaces the matched substring with a replacement substring.
• split A String method that uses a regular expression or a fixed string to break a string into an array of substrings.

_{Source: MDC}

So to answer your question, as the others have said:

/pattern/.test(txt)

Or, if it is more convenient for your particular use, this is equivalent:

txt.search(/pattern/) !== -1

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var b = /pattern/.test(txt);

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/pattern/.test(txt);

E.g.:

/foo \w+/.test("foo bar");

It returns true for a match, just like IsMatch.

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var regex = new RegExp(pattern);
var b = regex.test(text);

You can also use var b = /pattern/.test(text) but then you can't use a variable for the regex pattern.