CODEWITHSUNDEEP
javascriptnode.js
temesgen
temesgen

Reputation: 161

What is the cause of "Cannot read property 'replace' of undefined" in a node.js app

I am trying to form a URL by joining different elements. I am getting

TypeError: Cannot read property 'replace' of undefined.

When I am running the following code. Any suggestion is much appreciated!

...
function joinUrlElements() {
    "use strict";
    var re1 = new RegExp('^\\/|\\/$', 'g'),
        elts = Array.prototype.slice.call(arguments);
    return elts.map(function (element) {
        return element.replace(re1, "");
    }).join('/');
}
....

Upvotes: 1

Views: 4956

Answers (2)

Sonicd300
Sonicd300

Reputation: 2049

One of the arguments when you are calling this function causes an element of the array to be "undefined" and when map tries to operate on this item it throws the error.

Upvotes: 0

Suren Srapyan
Suren Srapyan

Reputation: 68645

This means that your elts has a item, which value is set to undefined.

Also with ES6 you ca use rest parameters which will replace using arguments variable in your case.

See an example

function joinUrlElements(...args) {
    var re1 = new RegExp('^\\/|\\/$', 'g');

    return args.map(function (element) {
        return element.replace(re1, "");
    }).join('/');
}

console.log(joinUrlElements('first', 'second', 'third'));

Upvotes: 1

Related Questions