@pelevesque/has_required_substrings_at_sums

has_required_substrings_at_sums

Checks if a string has required substrings after given sums.

Related Packages

https://github.com/pelevesque/has_required_substrings_at_indexes
https://github.com/pelevesque/has_prohibited_substring_at_sums
https://github.com/pelevesque/has_prohibited_substring_at_indexes

Node Repository

https://www.npmjs.com/package/@pelevesque/has_required_substrings_at_sums

Installation

npm install @pelevesque/has_required_substrings_at_sums

Tests

Standard Style & Unit Tests

npm test

Unit Tests & Coverage

npm run cover

Usage

Parameters

str                (required)
requiredSubstrings (required)
options            (optional) default = { substringsToDigits = null, sumPlainDigits = true,  allowSubstringBleeding = false }

Requiring

const hasRequiredSubstringsAtSums = require('@pelevesque/has_required_substrings_at_sums')

Basic Usage

@see https://github.com/pelevesque/sum-digits to understand how the sum is calculated.

requiredSubstrings is an object of sum -> substring pairs. true is returned if all substrings are found directly following their associated sums.

const str = '123a45'
const requiredSubstrings = { 1: 'a' }
const result = hasRequiredSubstringsAtSums(str, requiredSubstrings)
// result === false

const str = '123a45'
const requiredSubstrings = { 6: 'a' }
const result = hasRequiredSubstringsAtSums(str, requiredSubstrings)
// result === true

const str = '123man45dinosaur'
const requiredSubstrings = { 6: 'man', 15: 'dinosaur' }
const result = hasRequiredSubstringsAtSums(str, requiredSubstrings)
// result === true

// the substring must come directly after the sum (here b is directly after the sum, not a)
const str = '123ba45'
const requiredSubstrings = { 6: 'a' }
const result = hasRequiredSubstringsAtSums(str, requiredSubstrings)
// result === false

SubstringsToDigits

You can use the substringsToDigits object to give numeric values to substrings so that they are counted during summing.

const str = '123!$$$a'
const requiredSubstrings = { 15: 'a' }
const substringsToDigits = { '!': 4, '$$$': 5 }
const result = hasRequiredSubstringsAtSums(str, requiredSubstrings, {
  substringsToDigits: substringsToDigits
})
// result === true

SumPlainDigits Flag

You can set the sumPlainDigits flag to false if you only want to sum substringsToDigits.

In the following example, 1, 2, and 3 are not summed.

const str = '123!a'
const requiredSubstrings = { 4: 'a' }
const substringsToDigits = { '!': 4 }
const sumPlainDigits = false
const result = hasRequiredSubstringsAtSums(str, requiredSubstrings, {
  substringsToDigits: substringsToDigits,
  sumPlainDigits: sumPlainDigits
})
// result === true

AllowSubstringBleeding Flag

The allowSubstringBleeding flag is false by default. It it used when you want to allow the last substring to be incomplete if the string is too short. In the following example, the last substring canal starts at the correct index, but remains incomplete since the string ends. Normally this would return false. With allowSubstringBleeding set to true, it returns true.

const str = '123can'
const requiredSubstrings = { 6: 'canal' }
const allowSubstringBleeding = true
const result = hasRequiredSubstringsAtSums(str, requiredSubstrings, {
  allowSubstringBleeding: allowSubstringBleeding
})
// result === true