# Interpolate Params
## Installation
```shell
npm install interpolate-params --save
```
Then, in your app:
```js
var interpolateParams = require('interpolate-params').interpolateParams;
// or
var interpolateParamsInFirstMatch = require('interpolate-params').interpolateParamsInFirstMatch;
```
## API
* [`interpolateParams(pattern, params, [map])`](#interpolateParams)
* [`interpolateParamsInFirstMatch(patterns, params)`](#interpolateParamsInFirstMatch)
### interpolateParams(pattern, params, [map])
Interpolates `params` in the given parameterized `pattern`, using an optional `map` function (see its uses in the examples below).
If all `pattern` parameters appear in `params`, and `map` doesn't return `null`, the interpolation is considered successful. In this case, the interpolated pattern is returned along with the remaining params.
Otherwise, `interpolateParams` returns `null`.
`pattern` parameters must have letters only.
#### Example 1
```js
var result = interpolateParams(
'/users/:userId/friends/:friendId/photo',
{
friendId: '123',
userId: '456',
mood: 'Awesome'
}
);
/*
Returns:
{
interpolatedPattern: '/users/456/friends/123/photo',
remainingParams: {
mood: 'Awesome'
}
}
*/
```
#### Example 2
```js
var result = interpolateParams(
'/users/:userId/friends/:friendId/photo',
{
friendId: '123',
userId: '456',
mood: 'Awesome'
},
function(param, value) {
switch (param) {
case 'userId':
return value === '456' ? 'Misha' : null;
case 'friendId':
return value === '123' ? 'David' : null;
default:
return null;
}
}
);
/*
Returns:
{
interpolatedPattern: '/users/Misha/friends/David/photo',
remainingParams: {
mood: 'Awesome'
}
}
*/
```
#### Example 3
```js
var result = interpolateParams(
'/users/:userId/friends/:friendId/photo',
{
friendId: '999',
userId: '456',
mood: 'Awesome'
},
function(param, value) {
switch (param) {
case 'userId':
return value === '456' ? 'Misha' : null;
case 'friendId':
return value === '123' ? 'David' : null;
default:
return null;
}
}
);
/*
Returns:
null
because friendId !== '123'
*/
```
#### Example 4
```js
var result = interpolateParams(
'/users/:userId/friends/:friendId/photo',
{
friendId: '123',
mood: 'Awesome'
}
);
/*
Returns:
null
because `userId` is not in `params`.
*/
```
### interpolateParamsInFirstMatch(patterns, params)
Interpolates `params` in one of the parameterized `patterns`. Every pattern can have and optional `map` function. If none of the `patterns` match, `interpolateParamsInFirstMatch` returns `null`. Otherwise, it returns the first successful interpolation.
#### Example 1
```js
function paramsMap(param, value) {
switch (param) {
case 'userId':
return value === '456' ? 'Misha' : null;
case 'friendId':
return value === '123' ? 'David' : null;
default:
return null;
}
}
var result = interpolateParamsInFirstMatch(
[
{ pattern: '/users/:userId/friends/:friendId/photo', map: paramsMap },
{ pattern: '/users/:userId/friends/:friendId' },
{ pattern: '/users/:userId/friends' },
{ pattern: '/users/:userId' },
{ pattern: '/users' }
],
{
userId: '456',
friendId: '999',
mood: 'Awesome'
}
);
/*
Returns:
{
interpolatedPattern: '/users/456/friends/999',
remainingParams: {
mood: 'Awesome'
}
}
because the first pattern requires friendId === '123'
*/
```
#### Example 2
```js
var result = interpolateParamsInFirstMatch(
[
{ pattern: '/users/:userId/friends/:friendId/photo' },
{ pattern: '/users/:userId/friends/:friendId' },
{ pattern: '/users/:userId/friends' },
{ pattern: '/users/:userId' },
{ pattern: '/users' }
],
{
friendId: '123',
mood: 'Awesome'
}
);
/*
Returns:
{
interpolatedPattern: '/users',
remainingParams: {
friendId: '123',
mood: 'Awesome'
}
}
because every other pattern requires `userId` to be in params.
*/
```
#### Example 3
```js
var result = interpolateParamsInFirstMatch(
[
{ pattern: '/users/:userId/friends/:friendId/photo' },
{ pattern: '/users/:userId/friends/:friendId' },
{ pattern: '/users/:userId/friends' },
{ pattern: '/users/:userId' }
],
{
friendId: '123'
}
);
/*
Returns:
null
because all the patterns require `userId` to be in params.
*/
```
## Running Tests
```shell
npm test
```
## License
[MIT](http://moroshko.mit-license.org)