- Categories: JavaScript Methods, JavaScript Reference, Reference
Quick Reference
The Array every() method executes a function for each array element, returning true if the function returns true for all elements or false if the function returns false for at least one element.
<!-- html element to place output -->
<p id="my_ages"></p>
// array
let ages = [9, 23, 33, 43];
// function to run
function check_ages(age) {
return age >= 18;
}
// output true or false to the HTML element
document.getElementById('my_ages').innerHTML = 'It is ' + ages.every(check_ages) + ' that all ages in the array are 18 and older.';
The way this works (see Syntax section below):
- The every() method cycles through the items in the array and uses the function to determine if all of the ages are greater than or equal to 18; if so, the output is true; if not, the output is false
Output
It is false that all ages in the array are 18 and older.
Syntax
array.every(function(currentValue, index, arr), thisValue)
Parameters
| Parameter | Description |
|---|---|
| function() | A function to be run for each element in the array (required) |
| currentValue | The value of the current element (required) |
| index | The index of the current element |
| arr | The array of the current element |
| thisValue | A value passed to the function as its "this" value (default is undefined) |
We’d like to acknowledge that we learned a great deal of our coding from W3Schools and TutorialsPoint, borrowing heavily from their teaching process and excellent code examples. We highly recommend both sites to deepen your experience, and further your coding journey. We’re just hitting the basics here at 1SMARTchicken.
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JAVASCRIPT NOTES:
- When using JavaScript, single or double quotation marks are acceptable and work identically to one another; choose whichever you prefer, and stay consistent
- JavaScript is a case-sensitive language; firstName is NOT the same as firstname
- Arrays count starting from zero NOT one; so item 1 is position [0], item 2 is position [1], and item 3 is position [2] … and so on
- JavaScript variables must begin with a letter, $, or _
- JavaScript variables are case sensitive (x is not the same as X)
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