Fix performance issue that affects flat object with multiple (thousands) keys

[pedrodurek]

Closes #1991

In this PR, I've simplified the approach for inferring the return type by directly returning the value of a specified key, rather than using conditional type to verify the presence of all KeyWithOrdinalPlural, KeyWithPlural, and Key within Res before returning the value.

Here are the complexity results for the old and new approaches:

Old approach

• N = Number of sub-keys in the same key or namespace
• KeyWithPlural = 6
• KeyWithOrdinalPlural = 6

Complexity: O((KeyWithPlural * N) + (KeyWithOrdinalPlural * N) + N) = O(13 * N)

New approach

Complexity: O(1) - constant time

Checklist

• only relevant code is changed (make a diff before you submit the PR)
• run tests npm run test
• tests are included
• commit message and code follows the Developer's Certification of Origin

Checklist (for documentation change)

• only relevant documentation part is changed (make a diff before you submit the PR)
• motivation/reason is provided
• commit message and code follows the Developer's Certification of Origin

[coveralls]

coverage: 92.36%. remained the same when pulling df6c31c on pedrodurek:fix-performance-issue into 815cd83 on i18next:master.

[adrai]

included in v23.3.0

[quimeyruffa]

Hi! I got this error in one of the files of the node modules, do you know why? Has anyone else experienced this?

[0m[91m./node_modules/i18next/index.d.ts:834:69
Type error: '?' expected.

[adrai]

@quimeyruffa Which ts version are you using? And please provide a repruducible example.

[quimeyruffa]

@adrai
I am using version v23.3.0, and this is my i18n configuration.

import i18n from 'i18next';
import { initReactI18next } from 'react-i18next';
import es from './locales/AR.json'

const resources = {
    es: {
        translation: es
    }
}

i18n.use(initReactI18next).init({
    resources,
    defaultNS: "translation",
    fallbackLng: "es-AR",
    lng: "es-AR",
    debug: false,
  })

export const loadLanguage = (locale?: string) => {
    if (!locale) return

    import(`./locales/${locale}.json`).then((resources) => {
        i18n.addResourceBundle(locale, "translation", resources)
        i18n.changeLanguage(locale)
    })
}

[adrai]

@quimeyruffa I mean the TypeScript version... and btw: that's not a reproducible example... please provide a reproducible example like a github repo or similar.

[quimeyruffa]

Oh, sorry, I misunderstood, the version is. "typescript": "4.3.5"
The code itself cannot be sent due to company policy, but the error itself occurs at build-time and is related to the loadLanguage() function.
Here is the package.json.

{
  "name": "pharma1",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "NODE_OPTIONS='--openssl-legacy-provider' next dev -p 3008",
    "build": "next build",
    "start": "next start",
    "cy:open": "cypress open",
    "cy:run": "cypress run",
    "cy:install": "cypress install",
    "test:unit": "NODE_ENV=test jest --silent --env=jsdom",
    "test:unit:verbose": "NODE_ENV=test jest --verbose --env=jsdom",
    "test:unit:debug": "DEBUG=* npm run test:unit --silent=false",
    "test:e2e": "NODE_ENV=test npm run cy:run",
    "test:watch": "jest --watchAll",
    "test:coverage": "jest --watch=false --coverage"
  },
  "dependencies": {
    "@material-ui/core": "4.11.0",
    "@material-ui/icons": "4.9.1",
    "@material-ui/lab": "4.0.0-alpha.57",
    "@material-ui/styles": "4.10.0",
    "@xstate/react": "1.5.1",
    "autosuggest-highlight": "3.1.1",
    "axios": "0.21.1",
    "classnames": "^2.3.1",
    "compression": "^1.7.4",
    "cors": "^2.8.5",
    "date-fns": "2.15.0",
    "express": "^4.18.2",
    "faker": "5.1.0",
    "framer-motion": "4.1.17",
    "i18next": "^23.3.0",
    "js-cookie": "3.0.0",
    "msw": "0.34.0",
    "next": "11.1.0",
    "polished": "4.1.3",
    "pusher-js": "7.0.2",
    "rc-pagination": "3.0.3",
    "react": "17.0.1",
    "react-dom": "17.0.1",
    "react-dropzone": "11.2.3",
    "react-error-boundary": "3.0.2",
    "react-google-recaptcha": "2.1.0",
    "react-hook-form": "6.4.1",
    "react-i18next": "^13.0.2",
    "react-perfect-scrollbar": "1.5.8",
    "styled-components": "5.1.1",
    "styled-system": "5.1.5",
    "swr": "0.5.6",
    "typeface-source-sans-pro": "1.1.5",
    "xstate": "4.12.0"
  },
  "devDependencies": {
    "@next/bundle-analyzer": "11.1.0",
    "@testing-library/cypress": "8.0.0",
    "@testing-library/dom": "8.1.0",
    "@testing-library/jest-dom": "5.11.4",
    "@testing-library/react": "12.0.0",
    "@testing-library/user-event": "13.2.1",
    "@types/faker": "5.1.2",
    "@types/jest": "27.0.0",
    "@types/node": "16.6.0",
    "@types/react": "17.0.17",
    "@types/styled-components": "5.1.4",
    "@types/styled-system": "5.1.10",
    "babel-jest": "27.0.6",
    "babel-plugin-styled-components": "1.11.1",
    "cypress": "8.2.0",
    "husky": "7.0.1",
    "jest": "27.0.6",
    "jest-dom": "4.0.0",
    "prettier": "2.1.2",
    "typescript": "4.3.5"
  }
}

[adrai]

sorry, I'm unable to help without a reproducible example, but if the error occurs in loadLanguage, your build setup might be wrong...

[quimeyruffa]

this is the build log

info  - Checking validity of types...
Failed to compile.

./node_modules/i18next/index.d.ts:834:69
Type error: '?' expected.

  832 | type ParseKeysByFallbackNs<Keys extends $Dictionary> = _FallbackNamespace extends false
  833 |   ? never
> 834 |   : _FallbackNamespace extends (infer UnionFallbackNs extends string)[]
      |                                                                     ^
  835 |   ? Keys[UnionFallbackNs]
  836 |   : Keys[_FallbackNamespace & string];
  837 | 
error Command failed with exit code 1.

[pedrodurek]

This syntax is only supported in typescript V4.5 or higher, I'll put a PR up to change the syntax here.