Fake Database

fake-database.js

const fs = require('fs')

class FakeDatabase {
  constructor(dbPath) {
    this._filePath = dbPath || './data.json'
    this._data = JSON.parse(fs.readFileSync(this._filePath))
    this._idBase = Math.max.apply(null, this._data.map(i => i.id))
  }

  _idGen() {
    this._idBase += 1
    return this._idBase
  }

  _sync() {
    fs.writeFile(this._filePath, JSON.stringify(this._data))
  }

  create(payload) {
    payload.id = this._idGen()
    this._data.push(payload)
    this._sync()
    return payload
  }

  remove(id) {
    let index = -1
    this._data.find((item, idx) => {
      if (item.id === id) {
        index = idx
        return true
      }      
    })
    if (index !== -1) {
      this._data.splice(index, 1)
      this._sync()
      return {ok: 200}
    }
    return null
  }

  get(id) {
    return this._data.find(item => item.id === id)
  }

  update(id, payload) {
    const item = this.get(id)
    if (!item) {
      return null
    }
    for(const key in payload) {
      if (key !== 'id') {
        item[key] = payload[key]
      }
    }
    this._sync()
    return item
  }

  search(fields) {
    const result = []
    this._data.forEach(item => {
      let isMatch = true
      for(const key in fields) {
        if (fields[key] !== item[key]) {
          isMatch = false
          break
        }
      }
      if (isMatch) {
        result.push(item)
      }
    })
    return result
  }
}

module.exports = FakeDatabase