CODEWITHSUNDEEP
javascriptecmascript-6
Aubergine
Aubergine

Reputation: 6042

How to pass external scope variable to foreach function

I want the domMatch to be visible inside for each arrow function, if the body of the function can see this of outer scope which in my full case is a class there should also be a way to pass domMatch object. 

            let tr = document.createElement("tr");

            let domMatch = {};

            domMatch.status = this.status;
            ... other props


            Object.getOwnPropertyNames(domMatch).forEach(function (domMatchField, a, b, domMatch) { // domMatch is undefined
                let cell = tr.insertCell(-1);

                cell.innerText = domMatch[domMatchField];

            });

Upvotes: 2

Views: 4517

Answers (1)

Jamiec
Jamiec

Reputation: 136134

The problem is that you're trying to pass the variable domMatch through the callback function in forEach - this function accepts (at most) 3 arguments so of course the fourth will be undefined

Just omit that argument, and domMatch should be available inside the inner scope.

var domMatch = {};
domMatch.status = "foo";

Object.getOwnPropertyNames(domMatch).forEach(function(key, index, arr){
   console.log("iterating over key:", key);
   console.log("index:",index);
   console.log("Original array:", arr);
   // Now the important bit!
   console.log("domMatch", domMatch);
});

Upvotes: 3

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