Interpolate Params

Installation

npm install interpolate-params --save

Then, in your app:

var interpolateParams = require('interpolate-params').interpolateParams;
// or
var interpolateParamsInFirstMatch = require('interpolate-params').interpolateParamsInFirstMatch;

API

• interpolateParams(pattern, params, [map])
• interpolateParamsInFirstMatch(patterns, params)

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

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

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

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

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

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

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

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

npm test

License

MIT