Automatically generates migration files from your sequelize models

sequelize-schema-file-generator.js

const fs = require('fs')

const { sequelize } = require('./api/db/models')

const { models } = sequelize

function toSnakeCase(str, upper) {
  if (str.split().every(s => s.toLowerCase() === s)) return str

  const snake = str.replace(/([A-Z])/g, $1 => `_${$1.toLowerCase()}`)
  return upper ? snake.toLowerCase() : snake
}

Object.keys(models).forEach(model => {
  const { attributes } = models[model]

  Object.keys(attributes).forEach(column => {
    delete attributes[column].Model
    delete attributes[column].fieldName
    delete attributes[column].field

    // console.log(column, toSnakeCase(column))
    attributes[column].field = `${toSnakeCase(column, true)}`

    Object.keys(attributes[column]).forEach(property => {
      if (property.startsWith('_')) {
        delete attributes[column][property]
      }
    })

    if (typeof attributes[column].type !== 'undefined') {
      if (
        typeof attributes[column].type.options !== 'undefined' &&
        typeof attributes[column].type.options.toString === 'function'
      ) {
        attributes[column].type.options = attributes[
          column
        ].type.options.toString(sequelize)
      }

      if (typeof attributes[column].type.toString === 'function') {
        attributes[column].type = attributes[column].type.toString(sequelize)
      }
    }
  })

  let schema = JSON.stringify(attributes, null, 4)
  const { tableName } = models[model]
  const indexes = ['\n']

  if (models[model].options.indexes.length) {
    models[model].options.indexes.forEach(obj => {
      indexes.push('        .then(() => {')
      indexes.push('            return queryInterface.addIndex(')
      indexes.push(`                '${tableName}',`)
      indexes.push(`                ['${obj.fields.join("','")}']`)

      const opts = {}
      if (obj.name) {
        opts.indexName = obj.name
      }
      if (obj.unique === true) {
        opts.indicesType = 'UNIQUE'
      }
      if (obj.method === true) {
        opts.indexType = obj.method
      }
      if (Object.keys(opts).length) {
        indexes.push(`                , ${JSON.stringify(opts)}`)
      }

      indexes.push('            )')
      indexes.push('        })')
    })
  }

  schema = schema
    .split('\n')
    .map(line => `            ${line}`)
    .join('\n')

  const template = `module.exports = {
    up: async queryInterface => {
        await queryInterface.createTable('${tableName}', ${schema})
    },
    down: async queryInterface => {
        await queryInterface.dropTable('${tableName}')
    }
}
`

  // const d = new Date()

  // const filename = `${[
  //   d.getFullYear(),
  //   d.getMonth() + 1,
  //   d.getDate(),
  //   d.getHours(),
  //   d.getMinutes(),
  //   d.getSeconds(),
  // ]
  //   .map(num => (num <= 60 && (num + 100).toString().substring(1)) || num)
  //   .join('')}-${models[model].tableName}`

  fs.writeFileSync(`./migrations/000-${models[model].tableName}.js`, template)
})