starscream

0.1.14 • Public • Published

Deprecated in favour of AC/DC

starscream

Asynchronous JSON transformation

starscream

Installation

npm install starscream --save

Usage

var starscream = require('starscream')
var original = {
  source: {
     path: "robots in disguise"
  }
}
var options = {
  mapping: [{
    reader: {
      type: "jsonPointer",
      path: "/source/path"
    },
    transformer: {
      type: "uppercase"
    },
    writer: {
      type: "jsonPointer",
      path: "destination/path"
    }
  }]
}
starscream(options, original, function(err, transformed) {
   assert.equal(transformed.destination.path, 'ROBOTS IN DISGUISE')
})

Mapping Shorthand (Array Based)

var options = {
  mapping: [
    "/source/path/a",
    "/source/path/b",
  ]
}

Reads the value at /source/path/a in the original document, and writes it to /source/path/a in the transformed document

var options = {
  mapping: [{
    "/source/path/a": "/destination/path/a"
  }]
}

Reads the value at /source/path/a in the original document, and writes it to /destination/path/a in the transformed document

var options = {
  mapping: [{
    reader: "/source/path/a",
    transformer: "uppercase",
    writer: "/destination/path/a"
  }, {
    reader: "/source/path/b",
    transformer: "uppercase",
    writer: "/destination/path/b"
  }
}]

Reads the value at /source/path/a in the original document, transforms it to uppercase, and writes it to /destination/path/a in the transformed document

Mapping Shorthand (Object Based)

var options = {
  mapping: {
    "/source/path/a": "/destination/path/a",
    "/source/path/b": "/destination/path/b"
  }
}

Reads the value at /source/path/a in the original document, and writes it to /destination/path/a in the transformed document

var options = {
  mapping: {
    "/source/path/a": {
      transformer: "uppercase"
    },
    "/source/path/b": {
      transformer: "lowercase"
    }
  }
}

Reads the value at /source/path/a in the original document, transforms it to uppercase, and writes it to /source/path/a in the transformed document

var options = {
  mapping: {
    "/source/path/a": {
      transformer: "uppercase",
      writer: "/destination/path/a"
    },
    "/source/path/b": {
      transformer: "lowercase",
      writer: "/destination/path/b"
    },
  }
}

Reads the value at /source/path/a in the original document, transforms it to uppercase, and writes it to /destination/path/b in the transformed document

Using multiple sources for a single mapping

var options = {
  mapping: [{
    reader: {
      type: "serial",
      reader": [{
        type: "jsonPointer",
        path: "/source/path/a"
      }, {
        type: "jsonPointer",
        path: "/source/path/b"
      }],
    },
    writer": {
      type: "jsonPointer",
      path: "/destination/path"
    }
  }]
}

Reads the values at /source/path/a and /source/path/b in the original document, and inserts them as an array into the transformed document at '/desination/path'

Shorthand

var options = {
  mapping: [{
    reade": {
      type: "serial",
      reader: [
        "/source/path/a",
        "/source/path/b"
      }]
    },
    writer: {
      type: "jsonPointer",
      path: "/destination/path"
    }
  }]
}

The same shorthand rules apply

Aggregating Transformers

var options = {
  mapping: [{
    reader: {
      type: "serial",
      readers: [{
        type: "jsonPointer",
        path: "/source/path/a"
      }, {
        type: "jsonPointer",
        path: "/source/path/b"
      }],
    },
    transformer: {
      type: "concatenate",
      separator: "_"
    },
    writer: {
      type: "jsonPointer",
      path: "/destination/path"
    }
  }]
}

Reads the values at /source/path/a and /source/path/b from the original document, combines them with a underscore (_) and writes them to /destination/path in the transformed document

Chaining Transformers

var options = {
  mapping: [{
    reader: "/source/path"
    transformer: {
      type: "serial",
      transformers: [{
        type: "uppercase"
      }, {
        type: "prefix",
        text: "foo-"
      }]
    },
    writer": {
      type: "jsonPointer",
      path: "/destination/path"
    }
  }]
}

Reads the values at /source/pathin the original document, transforms it to uppercase, adds the foo- prefix and writes it to /destination/path in the transformed document

Iteration

You can iterate over arrays using the mapSeries transformer

    [
        {
            "reader": "/source/path",
            "transformer": {
                "type": "mapSeries",
                "transformer": "uppercase"
            },
            "writer": "/destination/path"
        }
    ]

Reads the array at /source/path and transforms each element to upper case before writing the array to /destination/path

Out of the box readers

jsonPointer (default)

var options = {
  mapping: [{
    reader: {
      "path": "/source/path"
      "ignoreMissing": "true"
    }
    writer: "/destination/path"
  }]
}

Reads the value at /source/path. If the path is missing and ignoreMissing is false (the defult) return undefined instead of erroring

property

var options = {
  mapping: [{
    reader: {
      "type": "property",
      "path": "source.path",
      "ignoreMissing": "true"
    }
    writer: "/destination/path"
  }]
}

Reads the value at source.path. If the path is missing and ignoreMissing is false (the defult) return undefined instead of erroring

Writers of the box readers

jsonPointer

var options = {
  mapping: [{
    reader: {
      "/source/path"
    writer: {
      "path": "/destination/path",
      "ignoreMissing": "true"
    }
  }]
}

Writes the value to /destination/path. If the value is undefined and ignoreMissing is true (the default) will not write anything, otherwise writes the value as undefined

property

var options = {
  mapping: [{
    reader: "/source/path"
    writer: {
      "type": "property",
      "path": "destination.path",
      "ignoreMissing": "true"
    }
  }]
}

Writes the value to /destination/path. If the value is undefined and ignoreMissing is true (the default) will not write anything, otherwise writes the value as undefined

Out of the box transformers

mapSeries

var options = {
  mapping: [{
    reader: "/source/path"
    transformer: {
      "type": "mapSeries",
      "transformer": "uppercase"
    }
    "toggle",
    writer: "/destination/path"
  }]
}

toggle

var options = {
  mapping: [{
    reader: "/source/path"
    transformer: "toggle",
    writer: "/destination/path"
  }]
}

uppercase

var options = {
  mapping: [{
    reader: "/source/path"
    transformer: "uppercase",
    writer: "/destination/path"
  }]
}

lowercase

var options = {
  mapping: [{
    reader: "/source/path"
    transformer: "lowercase",
    writer: "/destination/path"
  }]
}

mutualExclusion

var options = {
  mapping: [{
    readers: [
      "/source/path/a",
      "/source/path/b"
    ],
    transformer: "mutualExclusion",
    writer: "/destination/path"
  }]
}

Writes either /source/path/a or /source/path/b (with preference for a)

conditional

var options = {
  mapping: [{
    readers: [
      "/source/path/a",
      "/source/path/b"
    ],
    transformer: "mutualExclusion",
    writer: "/destination/path"
  }]
}

Writes /source/path/b if /source/path/a is truthy

guard

var options = {
  mapping: [{
    readers: [
      "/source/path/a",
      "/source/path/b"
    ],
    transformer: "mutualExclusion",
    writer: "/destination/path"
  }]
}

Writes /source/path/b if /source/path/a is falsey

Custom Transformers

var options = {
  mapping: [{
    reader: "/source/path"
    transformer: {
      type: "dbLookup",
      collection: "refdata"
    },
    writer: {
      type: "jsonPointer",
      path: "/destination/path"
    }
  }],
  transformers: {
    dbLookup: function(config, value, cb) {
      db.collections(config.collection).findOne({ code: value }, cb)
    })
  }
}

Reads the value at /source/path in the original document, and cross references it an item of refdata. The same mechanism can be used for writing your own readers and writers too.

Package Sidebar

Install

npm i starscream

Weekly Downloads

6

Version

0.1.14

License

ISC

Unpacked Size

57.4 kB

Total Files

35

Last publish

Collaborators

  • guidesmiths_bot
  • feliun
  • ulisesgascon
  • cressie176