rangeit

rangeit

This module is an ES6 class for creating number ranges with step intervals. Basic usage is inspired by Python's range function, but with extra methods for validating values, accessing steps out of order and by index.

Installation

Rangeit can be installed using npm:

npm install rangeit

Testing

Unit tests are provided using Jest. They can be run using npm:

npm test

Usage

Example code is provided in the file examples/examples.js. They can be run from the project directory using npm:

npm run example

JSDOC

• Range
  • constructor
  • iterator
  • size
  • step
  • indexOf
  • inRange
  • wrap
  • clamp

Constructor

new Range(start, stop, step)

Creates a new number range object. If one number is passed, the range will be 0 to the given number. If two numbers are passed, the range will run from start to stop (inclusive). If three numbers are passed, the range will run from start to stop with interval step.

Parameters:

Param	Type	Description
start	Number	(optional) First value in range
stop	Number	Last value in range
step	Number	(optional) Step interval

Example

import { Range } from "rangeit";

const rng1 = new Range(10);      // (0,1,2,3,4,5,6,7,8,9,10)
const rng2 = new Range(1,10);    // (1,2,3,4,5,6,7,8,9,10)
const rng3 = new Range(1,10,2);  // (1,3,5,7,9)
const rng4 = new Range(10,1);    // (10,9,8,7,6,5,4,3,2,1)
const rng5 = new Range(10,1,-2); // (10,8,6,4,2)

Range objects can also be created with the range function:

import { range } from "rangeit";

const rng1 = range(10);      // (0,1,2,3,4,5,6,7,8,9,10)
const rng2 = range(1,10);    // (1,2,3,4,5,6,7,8,9,10)
const rng3 = range(1,10,2);  // (1,3,5,7,9)
const rng4 = range(10,1);    // (10,9,8,7,6,5,4,3,2,1)
const rng5 = range(10,1,-2); // (10,8,6,4,2)

Iterator

Range values can be iterated over in for of loops or using the spread operator, for instance:

import { range } from "rangeit";

for (const value of range(5)) {
    console.log(value);
}

console.log([...range(5)]);

Size

The size property gets the number of valid steps in the range.

import { range } from "rangeit";

const rng = range(5); // (0,1,2,3,4,5)
console.log(rng.size); // 6

Step

step(index)

The step method returns an arbitary step value from the range based on it's index.

Parameters:

Param	Type	Description
index	Number	The index of the step

import { range } from "rangeit";

const rng = range(1,10,2); // (1,3,5,7,9)
console.log(rng.step(2));  // 5

indexOf

indexOf(value)

Returns the index of a given range step value, or -1 if the value is not in the range.

Parameters:

Param	Type	Description
value	Number	Step value to find

import { range } from "rangeit";

const rng = range(1,10,2);   // (1,3,5,7,9)
console.log(rng.indexOf(5)); // 2 

inRange

inRange(value)

Returns whether the given value is a valid step within the current range

Parameters:

Param	Type	Description
value	Number	Value to test

import { range } from "rangeit";

const rng = range(1,10,2); // (1,3,5,7,9)
console.log(rng.inRange(-1)); // false
console.log(rng.inRange(10)); // false
console.log(rng.inRange(6));  // false
console.log(rng.inRange(5));  // true

wrap

wrap(value)

Wraps the given value within the range. If the value is above the maximum, it's wrapped back from the minimum and vice versa. If the value is within the range, but is not a valid step, the closest valid step is returned.

Parameters:

Param	Type	Description
value	Number	Value to wrap

import { range } from "rangeit";

const rng = range(1,10); // (1,2,3,4,5,6,7,8,9,10)
console.log(rng.wrap(-2));  // 7
console.log(rng.wrap(12));  // 3
console.log(rng.wrap(1.5)); // 2

clamp

clamp(value)

Clamps the given value within the range. If the value is above the maximum, maximum is returned. If it is below the minimum, minimum is returned. If the value is within the range, but is not a valid step, the closest valid step is returned.

Parameters:

Param	Type	Description
value	Number	Value to clamp

import { range } from "rangeit";

const rng = range(1,10); // (1,2,3,4,5,6,7,8,9,10)
console.log(rng.clamp(-2));  // 1
console.log(rng.clamp(12));  // 10
console.log(rng.clamp(1.5)); // 2