@instructure/quiz-interactions/src/components/formula/Edit/GenerateSolutionsService.js

A React UI component Library for quiz interaction types.

import {searchForFormulaSolution} from './util'
import {loadMathjs} from '../common/util'

export default class GenerateSolutionsService {
  constructor({onStart, onSuccess, onFailure, onCancel}) {
    this._onStart = onStart
    this._onSuccess = onSuccess
    this._onFailure = onFailure
    this._onCancel = onCancel
    this._promise = Promise.resolve()
  }

  start(numSolutions, variables, formula, precision, scientificNotation = false) {
    this._onStart()

    const foundSolutions = []
    const promises = []

    for (let i = 0; i < numSolutions; i++) {
      promises.push(
        loadMathjs().then(() => {
          const solution = searchForFormulaSolution(
            variables,
            formula,
            foundSolutions,
            precision,
            scientificNotation,
          )
          if (solution !== null) {
            foundSolutions.push(solution)
          }
        }),
      )
    }

    const promise = Promise.all(promises).then(() => {
      if (!this.__promiseIsCurrent(promise)) {
        return
      }

      foundSolutions.length === numSolutions
        ? this._onSuccess(foundSolutions)
        : this._onFailure(foundSolutions)
    })

    this._promise = promise
    return promise
  }

  cancel() {
    this._promise = Promise.resolve()
    this._onCancel()
  }

  __promiseIsCurrent(promise) {
    return promise === this._promise
  }
}