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https://github.com/guidesmiths/starscream
Asynchronous JSON transformation
https://github.com/guidesmiths/starscream
hacktoberfest
Last synced: 22 days ago
JSON representation
Asynchronous JSON transformation
- Host: GitHub
- URL: https://github.com/guidesmiths/starscream
- Owner: guidesmiths
- Created: 2015-08-19T02:49:54.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2023-01-09T17:53:43.000Z (about 2 years ago)
- Last Synced: 2024-12-18T09:45:26.043Z (29 days ago)
- Topics: hacktoberfest
- Language: Gherkin
- Size: 121 KB
- Stars: 0
- Watchers: 11
- Forks: 0
- Open Issues: 9
-
Metadata Files:
- Readme: README.md
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README
# Deprecated in favour of [AC/DC](https://github.com/guidesmiths/acdc)
# starscream
Asynchronous JSON transformation
## Installation
```
npm install starscream --save
```
## Usage
```js
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)
```js
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
```js
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
```js
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)
```js
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
```js
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
```js
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
```js
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
```js
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
```js
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
```js
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/path```in 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
```js
[
{
"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)
```js
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
```js
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
```js
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
```js
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
```js
var options = {
mapping: [{
reader: "/source/path"
transformer: {
"type": "mapSeries",
"transformer": "uppercase"
}
"toggle",
writer: "/destination/path"
}]
}
```
#### toggle
```js
var options = {
mapping: [{
reader: "/source/path"
transformer: "toggle",
writer: "/destination/path"
}]
}
```
#### uppercase
```js
var options = {
mapping: [{
reader: "/source/path"
transformer: "uppercase",
writer: "/destination/path"
}]
}
```
#### lowercase
```js
var options = {
mapping: [{
reader: "/source/path"
transformer: "lowercase",
writer: "/destination/path"
}]
}
```
#### mutualExclusion
```js
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
```js
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
```js
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
```js
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.