Undefined array value found in .match function

Question

Undefined array value found in .match function

After calling the .string method on a string and assigning it to another variable, I am getting back an array containing the values for match, index, and input. However, when I attempt to access the second element in the array, it shows up as undefined. Can someone please explain why this is happening? Here's my code snippet:

var str = "hello world";
var matchArray = str.match("ell");

=>matchArray  = ["ell",index:1,input:"hello world"]

var index = matchArray[1];
console.log(index);

=>undefined

Any help would be greatly appreciated. Thank you!

javascript arrays methods match

Answer 1

Answer №1

let greeting = "hi there"
let resultArray = greeting.match("the");

resultArray is actually an instance of the Array data type in JavaScript. However, in JavaScript, arrays can also have properties because they are objects.

In this specific example, resultArray only contains the matches found in the string. The additional properties such as index and input are stored within the object representation of the array.

If you run console.dir(resultArray), you will see these extra properties along with the matches.

To access these properties, use typical object notation like resultArray.index or resultArray.input.

Answer 2

let greeting = "hi there"
let resultArray = greeting.match("the");

resultArray is actually an instance of the Array data type in JavaScript. However, in JavaScript, arrays can also have properties because they are objects.

In this specific example, resultArray only contains the matches found in the string. The additional properties such as index and input are stored within the object representation of the array.

If you run console.dir(resultArray), you will see these extra properties along with the matches.

To access these properties, use typical object notation like resultArray.index or resultArray.input.

Answer 3

Answer №2

Exploring the world of JavaScript can be quite fascinating. One unique aspect is that even though a matchArray is technically an array, in JS it's possible to expand any object with new members. This means that while the matchArray may have a length of 1, it also boasts additional properties like index and input. Give this code snippet a try:

...
console.log(matchArray.index);
console.log(matchArray.input);

If we wanted to create a similar object from scratch, we could achieve it as follows:

var hybridObj = [ "ell" ];  // Initially an array
hybridObj.index = 1;        // Adding custom properties
hybridObj.input = "hello world";

Answer 4

Exploring the world of JavaScript can be quite fascinating. One unique aspect is that even though a matchArray is technically an array, in JS it's possible to expand any object with new members. This means that while the matchArray may have a length of 1, it also boasts additional properties like index and input. Give this code snippet a try:

...
console.log(matchArray.index);
console.log(matchArray.input);

If we wanted to create a similar object from scratch, we could achieve it as follows:

var hybridObj = [ "ell" ];  // Initially an array
hybridObj.index = 1;        // Adding custom properties
hybridObj.input = "hello world";

Undefined array value found in .match function

Answer №1

Answer №2

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