Jshint：循环中的匿名函数（问题）

Question

My problem is similar to JSHint won't let me use 'forEach' in a 'for' loop

We have about 2k JS lines in currently project, recently included jshint checking, one common issue is the below sample code would throw

Don't make functions within a loop.

sample code:

var s1 = '12345'.split('');
var oo = { a: s1, b: s1, c: s1};

function odd(obj){
    var tmp = [];
    for (var key in obj){
        obj[key].forEach( function(val){
            if(val%2>0) tmp.push(val);
        });
    }
    return tmp;
}


odd(oo);

my fix was:

function odd(obj){
    var tmp = [], tmpFn;
    tmpFn = function(val){
        if(val%2>0) tmp.push(val);
    };
    for (var key in obj){
        obj[key].forEach(tmpFn);
    }
    return tmp;
}

I have checked, this works, but I am unsure if this is the right way to fix old code, would there be any unwanted side effects from this fix? or should I just ignore the warning, as the old code looks much cleaner?

EDIT : I missed a for loop, updated sample code with it.

Answer 1

Don't ignore that warning, it's really unnecessary to create a new function for each run of your loop.

This approach is better, and as long as you stay within the odd() function with the definition, it won't have any side effects, it will see the same variable states as it would as an anonymous function passed to forEach.

Edit: even if you do decide to ignore that warning, do it consistently - either use a jshint configuration which doesn't consider this a mistake, or add a jshint comment to temporarily disable this warning type inside the code (use jshint --verbose to get the warning code for selective toggling), don't let any displayed jshint warning go without notice, that defeats the purpose of having code analysis in the first place.