// CommonJS way:
const { matchLeftIncl, matchRightIncl, matchLeft, matchRight } = require('string-match-left-right')
// ES  Modules way:
import { matchLeftIncl, matchRightIncl, matchLeft, matchRight } from 'string-match-left-right'

{
  i: false,
  cb: undefined,
  trimBeforeMatching: false,
  trimCharsBeforeMatching: []
}

// K E Y
// -----
// test string with character indexes to help you count:
//
// test string:                a  b  c  d  e  f  g  h  i
// indexes of letters above:   0  1  2  3  4  5  6  7  8
//
// a is #0, b is #1 and so on. Look the digit under letter above.
//
// that is, c is number (term "number" further abbreviated as hash character "#") 2 or i is #8.
//
// we'll be using the same string "abcdefghi" below:

const { matchLeftIncl, matchRightIncl, matchLeft, matchRight } = require('string-match-left-right')

let res1 = matchLeftIncl('abcdefghi', 3, ['bcd'])
// 3rd character is "d" because indexes start from zero.
// We're checking the string to the left of it, "bcd", inclusive of current character ("d").
// This means, "bcd" has to end with existing character and the other chars to the left
// must match exactly:
console.log(`res1 = ${res1}`)
// => res1 = true

let res2 = matchLeft('abcdefghi', 3, ['ab', `zz`])
// neither "ab" nor "zz" are to the left of 3rd index, "d":
console.log(`res2 = ${res2}`)
// => res2 = false

let res3 = matchRightIncl('abcdefghi', 3, ['def', `zzz`])
// "def" is to the right of 3rd index (including it), "d":
console.log(`res3 = ${res3}`)
// => res3 = true

let res4 = matchRight('abcdefghi', 3, ['ef', `zz`])
// One of values, "ef" is exactly to the right of 3rd index, "d":
console.log(`res4 = ${res4}`)
// => res4 = true

const { matchLeftIncl, matchRightIncl, matchLeft, matchRight } = require('string-match-left-right')
// imagine you looped the string and wanted to catch where does attribute "class" start
// and end (not to mention to ensure that it's a real attribute, not something ending with this
// string "class").
// You catch "=", an index number 8.
// This library can check, is "class" to the left of it and feed what's to the left of it
// to your supplied callback function, which happens to be a checker "is it a space":
function isSpace(char) {
  return (typeof char === 'string') && (char.trim() === '')
}
let res = matchLeft('<a class="something">', 8, 'class', { cb: isSpace })
console.log(`res = ${JSON.stringify(res, null, 4)}`)
// => res = true

const { matchLeftIncl, matchRightIncl, matchLeft, matchRight } = require('string-match-left-right')

function startsWithZ(firstCharacter, wholeSubstring) {
  // console.log(`firstCharacter = ${JSON.stringify(firstCharacter, null, 4)}`)
  // console.log(`wholeSubstring = ${JSON.stringify(wholeSubstring, null, 4)}`)
  return wholeSubstring.startsWith('z')
}

const test01 = matchLeft('<div><b>aaa</b></div>', 5, ['<div>'])
console.log(`test01 = ${JSON.stringify(test01, null, 4)}`)
// => true, // the 5th index is left bracket of <b>. Yes, <div> is on the left.

const test02 = matchLeft('z<div ><b>aaa</b></div>', 7, ['<div>'])
console.log(`test02 = ${JSON.stringify(test02, null, 4)}`)
// => false, // the 7th index is left bracket of <b>. Yes, <div> is on the left.

const test03 = matchLeft('z<div ><b>aaa</b></div>', 7, ['<div'], { trimCharsBeforeMatching: [' >'] })
console.log(`test03 = ${JSON.stringify(test03, null, 4)}`)
// => true, // the 7th index is left bracket of <b>. Yes, <div> is on the left.

const test04 = matchLeft('z<div ><b>aaa</b></div>', 7, ['<div'], { cb: startsWithZ, trimCharsBeforeMatching: [' >'] })
console.log(`test04 = ${JSON.stringify(test04, null, 4)}`)
// => true, // the 7th index is left bracket of <b>. Yes, <div> is on the left.

const test05 = matchLeft('<div ><b>aaa</b></div>', 6, ['<div'], { cb: startsWithZ, trimCharsBeforeMatching: [' >'] }),
console.log(`test05 = ${JSON.stringify(test05, null, 4)}`)
// => false, // deliberately making the second arg of cb to be blank and fail startsWithZ