Package Exports

ranging

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Readme

ranging (JavaScript library)

Range helper classes based on iterators

Installation

Using npm:

npm install ranging

Using yarn:

yarn add ranging

Examples

Importing

const { Range } = require('ranging');
// ES6+
import { Range } from 'ranging';

Import specific modules `javascript const { NumberRange, StringRange } = require('ranging'); // ES6+ import { NumberRange, StringRange } from 'ranging';` ## Typescript support (only v1.1.0+) Before compiling, create a `tsconfig.json` file, or open it and make sure it contains the following lines: `json { "compilerOptions": { "lib": ["ES6"], // The number of libraries used may vary, as long as the "ES6" library is present "downlevelIteration": true } }`

Number ranges

Integers

A list of integers from 1 to 10 inclusive

const { NumberRange } = require('ranging');

const integers = [...new NumberRange().start(1).end(10)];
// integers: [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]

// it's same as
const sameIntegers = [...new NumberRange({ start: 1, end: 10 })];

// and same as
const sameIntegersTwo = [...new NumberRange(1, 10)];

Integers ranged with step of 2

const integers = [
  ...new NumberRange()
    .start(1)
    .end(10)
    .step(2)
];
// integers: [ 1, 3, 5, 7, 9 ]

// it's same as
const sameIntegers = [...new NumberRange(1, 10, 2)];

Floating point numbers

let floats = [
  ...new NumberRange()
    .start(2)
    .end(5)
    .step(0.5)
    .isFloat(true)
];
console.log(floats);
// [ 2, 2.5, 3, 3.5, 4, 4.5, 5 ]

floats = [
  ...new NumberRange()
    .start(2)
    .end(5)
    .isFloat(true)
];
console.log(floats);
// [ 2, 3, 4, 5 ]

Note: sum fractional floating point numbers with NumberRange.sum.
Approximation error

let sum = 0;
for (let i = 1; i <= 20; i++) {
  sum += i / 10;
}
console.log(sum);
// 20.999999999999996

Use of NumberRange.sum (expected answer)

console.log(
 new NumberRange()
   .start(0.1)
   .end(2)
   .step(0.1)
   .isFloat(true)
   .sum
);
// 21

Infinite generator

Use of NumberRange.integer without specifying end

let counter = 0;
const result = [];

for (let i of new NumberRange({ start: 1005 })) {
  const hex = i.toString(16);
  if (hex == hex.split('').reverse().join('')) {
    counter++;
    result.unshift(i);
  }
  if (counter === 10) break;
}
console.log(result);
// [ 1156, 1140, 1124, 1108, 1092, 1076, 1060, 1044, 1028, 1011 ]

Starting from 1005, executes until finds 10 numbers that are palindromes in hexadecimal notation. The result is presented in descending order.

Char Ranges

const { CharRange } = require('ranging');

console.log([
  ...new CharRange()
]);
// ['A', ..., 'Z']

So you can use this like NumberRange

console.log([
  ...new CharRange().start('a').end('f').step(2) // Note: step is an integer number
]);
// ['a', 'c', 'e']
// or
console.log([
  ...new CharRange({
    start: 'a',
    end: 'f',
    step: 2
  })
]);
// or
console.log([...new CharRange('a', 'f', 2)]);

String Ranges

This is almost the same as CharRange, only iterates over the passed string

const { StringRange } = require('ranging');

console.log([
  ...new StringRange().source('Hello world')
])
// ['H', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']

console.log([
  ...new StringRange({
    source: 'Hello world',
    start: 6,
    step: 2
  })
])
// [ ' ', 'o', 'l' ]

Date Ranges

Main date range

const { DateRange } = require('ranging');

console.log([
  ...new DateRange({
    start: new Date(),
    count: 5, // you can use `count` in all ranges if you set this, then that uses instead `end` property
    step: 5
  })
])
// [
//   2021-08-18T09:23:55.670Z,
//   2021-08-18T09:23:55.675Z,
//   2021-08-18T09:23:55.680Z,
//   2021-08-18T09:23:55.685Z,
//   2021-08-18T09:23:55.690Z
// ]

Sub ranges

You can use sub ranges, that names [timeUnit]Range for example: SecondRange, MinuteRange, etc

const { YearRange } = require('ranging');

console.log([
  ...new YearRange()
    .start(new Date())
    .step(1)
    .leepYear(true) // use this that your range consisted only of leap years
    .count(10)
])
// [
//   2024-08-18T09:34:01.866Z,
//   2028-08-18T09:34:01.866Z,
//   2032-08-18T09:34:01.866Z,
//   2036-08-18T09:34:01.866Z,
//   2040-08-18T09:34:01.866Z
// ]

Map, filter, length, reduce, sum (only NumberRange)

Map

const { StringRange } = require('ranging');

const word = new StringRange().source('Some bad word').map((item) => (item === ' ' ? item : 'x'));
// or 
const word2 = new StringRange('Some bad word', (item) => (item === ' ' ? item : 'x'));

console.log([...word].join(''))
// xxxx xxx xxxx

Filter

const { NumberRange } = require('ranging');

const someSeq = new NumberRange({
  start: 10,
  end: 40,
  filter: (item) => item % 3 === 0 && item % 5 === 0
});

console.log([...someSeq]);
// [ 15, 30 ]

Reduce

const { StringRange } = require('ranging');

const word = new StringRange({
  source: 'Some bad word',
  map: (item) => (item === ' ' ? item : 'x')
});

console.log(word.reduce((prevValue, currValue) => prevValue + currValue, ''))
// xxxx xxx xxxx

Length

const { NumberRange } = require('ranging');

const someSeq = new NumberRange().end(9);
// or
const someSeq2 = new NumberRange(9);

console.log(someSeq.length);
// 9

Sum

This getter is designed to correctly sum floating point numbers

const { NumberRange } = require('ranging');

console.log(
  new NumberRange()
    .start(0.1)
    .end(2)
    .step(0.1)
    .isFloat(true)
    .sum
);
// 21
// or
console.log(new NumberRange(0.1, 2, 0.1).isFloat(true).sum)
// 21

ranging