Navigating through tslint: adhere to the one-variable-per-declaration rule

What is the best way to write code following this rule?

let exampleArray = [...];
for (let j = 0, k = exampleArray.length; j < k; j++) {
  ...
}

Answer №1

This piece of advice has become a classic in the world of JavaScript.

The tsLint rule is specifically crafted to prioritize readability within your code.

Many individuals typically store the length of an array in a variable believing it brings a performance advantage. However, if this is the sole reason behind doing so, the minimal performance boost may not outweigh the loss in readability (and when I personally tested it on JSPerf, it was actually slower).

Hence, this represents the standard "tsLint recommended solution"...

for (let i = 0; i < someArray.length; i++) {

In JavaScript, accessing the length property does not result in iterating through the entire array, making the impact negligible.

If you hold a different perspective, you have the option to disable the rule - here's how you can do it with a comment:

/* tslint:disable:one-variable-per-declaration */

Alternatively, you can achieve this via configuration settings:

"one-variable-per-declaration": false

Or you may choose to utilize the configuration flag that deactivates it solely for for loops:

"one-variable-per-declaration": [true, "ignore-for-loop"]

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