bimedia-objectmapper 
object mapper for node
Object Mapper Module
This module allow to map keys and values from an object to an other. Mapping uses a tranformation rules. There are 3 transformation rules types :
- identity : copy the attribute and value to the target object.
- alias : rename the attribute in the target object (value is unchanged).
- complex : apply tranformation rule provided to change attribute name and value.
Installation
npm install --save bimedia-objectmapper
Usage
 Simple usecase
var ObjectMapper = require('bimedia-objectmapper');
var mapper = objectMapper({'key':'clé'});
var result = mapper({key:'value'});
// {'clé': 'value'} Streams
var objectMapper = require('bimedia-objectmapper'),
fs = require('fs'),
JSONStream = require('JSONStream');
var mapper = objectMapper(rules);
fs.createReadStream('package.json')
.pipe(JSONStream.parse())
.pipe(mapper.stream())
.pipe(process.stdout);Â Arrays
var objectMapper = require('bimedia-objectmapper');
var mapper = objectMapper({'key':'clé'});
var sources = [{key:'value1'}, {key:'value2'}, {key:'value3'}];
var result = sources.map(mapper);
//[ { 'clé': 'value1' },
// { 'clé': 'value2' },
// { 'clé': 'value3' } ]Mapping rules definitions
Identity Rule
No specific rule is needed. Attribute is copied to target object.
Simple Rule (alias)
Declare a constant as attribute value. Example :
var rules = {
"trxpvptpv": "trxid"
};This rule renames trxpvptpv attribute in source object, to trxid in target object.
Complex Rule
Define an object matching the source attribute. Example :
var rules = {
'state' : {
name : 'currentState',
mapper : function (val) {
if (val == 'Y') {
return 'REFUNDED';
}
return val == 'N' ? 'REFUSED' : 'PENDING';
}
}
};Or directly with a function :
var rules = {
'state' : function (k, v) {
var value;
if (val == 'Y') {
value = 'REFUNDED';
}
value = val == 'N' ? 'REFUSED' : 'PENDING';
return {key: 'currentState', value: value};
}
}
};This 2 examples transforms the state attribute in source object to an currentState attribute in target object.
Options
Mapping can be customize with the second argmuent of ObjectMapper :
For instance to disable identity mapping by default :
var mapper = ObjectMapper(rules, {defaults: false});Or to specify a default mapping function :
var mapper = ObjectMapper(rules, {defaults: ObjectMapper.keys.camelCase});supported options
-
defaults: (function | boolean) define a default mapping function. By defautObjectMapper.identity.
