eslint-plugin-codebox/src/utils/TranspositionManager.js

A set of ESLint rules we use at Codebox

function swap(array, indexOne, indexTwo) {
  const a = array[indexOne]
  const b = array[indexTwo]
  array[indexTwo] = a // eslint-disable-line
  array[indexOne] = b // eslint-disable-line
}

export default class TranspositionManager {
  constructor(nodes) {
    this.nodes = nodes
    this.workOn = nodes.length - 1
    this.virtualTransposedState = nodes.slice()
  }

  canTranspose() {
    return this.workOn > 0
  }

  transpose() {
    let workNode = this.virtualTransposedState[this.workOn].shouldBe
    while (workNode === this.workOn && this.workOn > 0)
      workNode = this.virtualTransposedState[--this.workOn].shouldBe // eslint-disable-line
    swap(this.virtualTransposedState, this.workOn, workNode)
    const result = [this.virtualTransposedState[workNode], this.virtualTransposedState[this.workOn]]
    if (this.workOn < workNode) result.reverse()
    return result
  }
}