@iopa/router/src/reg-exp-router/trie.ts

Lightweight and fast router for IOPA applications

/* eslint-disable @rushstack/security/no-unsafe-regexp */
import type { ParamMap, IRouterContext } from './node'
import { Node } from './node'

export type { ParamMap } from './node'
export type ReplacementMap = number[]

interface IInitOptions {
  reverse: boolean
}

export class Trie {
  public context: IRouterContext = { varIndex: 0 }
  public root: Node

  public constructor({ reverse }: IInitOptions = { reverse: false }) {
    this.root = new Node({ reverse })
  }

  public insert(path: string, index: number): ParamMap {
    const paramMap: ParamMap = []

    /**
     *  - pattern (:label, :label{0-9]+}, ...)
     *  - /* wildcard
     *  - character
     */
    const tokens = path.match(/(?::[^\/]+)|(?:\/\*$)|./g)
    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
    // @ts-ignore
    this.root.insert(tokens, index, paramMap, this.context)

    return paramMap
  }

  public buildRegExp(): [RegExp, ReplacementMap, ReplacementMap] {
    let regexp = this.root.buildRegExpStr()

    let captureIndex = 0
    const indexReplacementMap: ReplacementMap = []
    const paramReplacementMap: ReplacementMap = []

    regexp = regexp.replace(
      /#(\d+)|@(\d+)|\.\*\$/g,
      // eslint-disable-next-line @typescript-eslint/naming-convention
      (_, handlerIndex, paramIndex) => {
        if (typeof handlerIndex !== 'undefined') {
          indexReplacementMap[++captureIndex] = Number(handlerIndex)
          return '$()'
        }
        if (typeof paramIndex !== 'undefined') {
          paramReplacementMap[Number(paramIndex)] = ++captureIndex
          return ''
        }

        return ''
      }
    )

    return [new RegExp(`^${regexp}`), indexReplacementMap, paramReplacementMap]
  }
}