Lookup values from a dictionary with aliasing, mapping, and flattenining.
npm install value-mapperLookup values from a dictionary with aliasing, mapping, and flattenining.
This is used by [doubleshot][doubleshot] to map values inside of content.
[doubleshot]: https://github.com/twolfson/doubleshot
npm install value-mapper``javascript
// Create a mapper
var ValueMapper = require('value-mapper'),
mapper = new ValueMapper({
'1 + 2': ['One', 'plus two'],
'One': function () {
this.sum = 1;
},
'plus two': function () {
this.sum += 2;
},
'= 3': 'equals three',
'equals three': function () {
assert.strictEqual(this.sum, 3);
}
});
// Lookup the values on a per-key basis
mapper.lookup('1 + 2', {
alias: true,
map: true
});
/*
[
function () {
this.sum = 1;
},
function () {
this.sum += 2;
}
]
*/
`
is a constructor function`js
/**
* Constructor for mapping values
* @param {Object} input Key-value pairs to map values across
*/
`To find values, use the
method`js
mapper.lookup(key);
mapper.lookup(key, options);
/**
* Resolve the value of a key
* @param {String} key Name to lookup value by
* @param {Object} [options] Flags to adjust how the mapping is performed
* @param {Boolean} [options.alias] If the value is a string, value = input[value]
* @param {Boolean} [options.map] If a value is an array, its values will be processed via the aliasing proxy.
* @param {Boolean} [options.flatten] If the value is an array and contains arrays, the array will be flattened.
* @param {Function[]} [options.middlewares] If provided, these functions will be appended to the array of middlewares.
* @returns {Object} retObj Container for value and meta information
* @returns {Mixed} retObj.value Aliased, mapped, and flattened copy of
* @returns {String[]} retObj.aliasesUsed Array of aliased keys used while looking up
* @returns {String[]} retObj.aliasesNotFound Array of aliased not found while looking up
*/
Examples
Here is an example using , alias, and flatten.`js
// A complex mapping
var mapper = ValueMapper({
'A fruit': 'A banana',
'A banana': function () {
this.color = 'yellow';
this.fruit = new Banana();
},
'is yellow': ['hasColor', 'assertColor'],
'when peeled is white': ['when peeled', 'is white'],
'when peeled': function () {
this.color = 'white';
this.fruit = this.fruit.peel();
},
'is white': ['hasColor', 'assertColor'],
'hasColor': function () {
assert(this.fruit.color);
},
'assertColor': function () {
assert.strictEqual(this.fruit.color, this.color);
}
}, {
alias: true,
map: true,
flatten: true
});// when mapped looks like
mapper.lookup('A fruit');
/*
function () {
this.color = 'yellow';
this.fruit = new Banana();
}
*/
mapper.lookup('is yellow');
/*
[
function () {
assert(this.fruit.color);
},
function () {
assert.strictEqual(this.fruit.color, this.color);
}
]
*/
mapper.lookup('when peeled is white');
/*
[
function () {
this.color = 'white';
this.fruit = this.fruit.peel();
},
function () {
assert(this.fruit.color);
},
function () {
assert.strictEqual(this.fruit.color, this.color);
}
]
*/
`Contributing
In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint via grunt and test via Licensed under the MIT license.