what's wrong with .match() javascript

jquery says: http://docs.jquery.com/JQuery_Core_Sty开发者_Go百科le_Guidelines#RegExp

All RegExp operations should be done using .test() and .exec(). "string".match() is no longer used.

Why is .match() not recommended?

Consider:

Given:

var Str             = 'Here are some words.';
var myRegex         = /(\w+)/ig;

.

With match():

var aWordList       = Str.match (myRegex);
var iLen            = aWordList.length;

for (var K=0;  K < iLen;  K++)
{
    console.log ('Word: ', K, ' --> ', aWordList[K]);
}

.

With exec():

var aWordList;
var K               = 0;

RegExp.lastindex    = 0;    //-- If this is omitted, nasty side-effects may occur.

while ( (aWordList = myRegex.exec (Str)) != null)
{
    console.log ('Word: ', K++, ' --> ', aWordList[0]);
}

.

See how much simpler exec() is?
(Me neither.)

Both functions are fully supported according to my chart (except that match() results also have the input member on IE).

I couldn't find a justification for the decision by the folks at jQuery.

A major benefit of exec is that it returns capturing groups. For example:

var s = "123456789"
var regex = /.(.)(..)/g;

match:

s.match(regex);
> [1234, 5678]

exec:

regex.exec(s);
> [1234, 2, 34]
regex.exec(s);
> [5678, 6, 78]

Reviewing the coding standards you've posted; the document contains many seemingly arbitrary guidelines. Obviously, it aims to achieve mostly consistency, so it is possible exec is preferred because it has more functionality - it has to be used on some occasions, so they might as well use it always.

On a personal note, I don't care much for guidelines without explanations, so it's a good thing you've asked. In many cases it leads to dogmatic or superstition-based programming.

This is a style thing.

The big difference is that match is called like so:

string.match(regex)

While test and exec are called like so:

regex.exec(string)