--description--

Say you have two strings that you would like to combine to create one message, such as below:

const str1 = "Hello";
const str2 = "World!";
const message = str1.push(str2);

Here, you'll get a TypeError with a message stating that str1.push is not a function. This is a common error message that confuses learners because you might know that .push() is certainly a function (for example, if you have used it to add items to arrays before).

But that's the key - .push() is not a String method, it's an Array method. Hence, it is “not a function” that you can find as a String method. If you change.push() to .concat(), a proper String method, our code runs as intended!

A good note to keep in mind when faced with a TypeError is to consider the data type you are trying to run a method or operation against. You'll likely find that it is not what you think, or the operation or method is not compatible with that type.

--questions--

--text--

Why does the following JavaScript code result in a TypeError?

const str1 = "Hello";
const str2 = "World!";
const message = str1.push(str2);

--answers--

The .push() method can only be used on objects, not strings.

The .push() method is not available for strings because it is an Array method.

The .push() method is incorrectly spelled and should be .pusch().

The TypeError is a result of a syntax error in the JavaScript code.

--video-solution--

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