rjrodger/gex

/* Copyright (c) 2011-2020 Richard Rodger, MIT License */

class Gexer {
  gexmap: { [key: string]: RegExp }
  desc: string = ''

  constructor(gexspec: string | string[]) {
    this.gexmap = {}

    if (null != gexspec) {
      let gexstrs = Array.isArray(gexspec) ? gexspec : [gexspec]

      gexstrs.forEach((str) => {
        this.gexmap[str] = this.re(this.clean(str))
      })
    }
  }

  dodgy(obj: any) {
    return null == obj || Number.isNaN(obj)
  }

  clean(gexexp: any) {
    let gexstr = '' + gexexp
    return this.dodgy(gexexp) ? '' : gexstr
  }

  match(str: any) {
    str = '' + str
    let hasmatch = false
    let gexstrs = Object.keys(this.gexmap)

    for (let i = 0; i < gexstrs.length && !hasmatch; i++) {
      hasmatch = !!this.gexmap[gexstrs[i]].exec(str)
    }
    return hasmatch
  }

  on(obj: any) {
    if (null == obj) {
      return null
    }

    let typeof_obj = typeof obj
    if (
      'string' === typeof_obj ||
      'number' === typeof_obj ||
      'boolean' === typeof_obj ||
      obj instanceof Date ||
      obj instanceof RegExp
    ) {
      return this.match(obj) ? obj : null
    } else if (Array.isArray(obj)) {
      let out = []
      for (let i = 0; i < obj.length; i++) {
        if (!this.dodgy(obj[i]) && this.match(obj[i])) {
          out.push(obj[i])
        }
      }
      return out
    } else {
      let outobj: any = {}
      for (let p in obj) {
        if (Object.prototype.hasOwnProperty.call(obj, p)) {
          if (this.match(p)) {
            outobj[p] = obj[p]
          }
        }
      }
      return outobj
    }
  }

  esc(gexexp: any) {
    let gexstr = this.clean(gexexp)
    gexstr = gexstr.replace(/\*/g, '**')
    gexstr = gexstr.replace(/\?/g, '*?')
    return gexstr
  }

  escregexp(restr: string) {
    return restr ? ('' + restr).replace(/[-[\]{}()*+?.,\\^$|#\s]/g, '\\$&') : ''
  }

  re(gs: string): RegExp | any {
    if ('' === gs || gs) {
      gs = this.escregexp(gs)

      // use [\s\S] instead of . to match newlines
      gs = gs.replace(/\\\*/g, '[\\s\\S]*')
      gs = gs.replace(/\\\?/g, '[\\s\\S]')

      // escapes ** and *?
      gs = gs.replace(/\[\\s\\S\]\*\[\\s\\S\]\*/g, '\\*')
      gs = gs.replace(/\[\\s\\S\]\*\[\\s\\S\]/g, '\\?')

      gs = '^' + gs + '$'

      return new RegExp(gs)
    } else {
      let gexstrs = Object.keys(this.gexmap)
      return 1 == gexstrs.length ? this.gexmap[gexstrs[0]] : { ...this.gexmap }
    }
  }

  toString() {
    let d = this.desc
    return '' != d ? d : (this.desc = 'Gex[' + Object.keys(this.gexmap) + ']')
  }

  inspect() {
    return this.toString()
  }
}

function Gex(gexspec: string | string[]): Gexer {
  return new Gexer(gexspec)
}

if ('undefined' !== typeof module) {
  module.exports = Gex
  module.exports.Gex = Gex
}

export default Gex

export { Gex }