chain.js

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chain.js

Given a target context, build a chainable API.

Example: chain(Array.prototype)([1, 2, 3, 4 ]).join(' ').valueOf();

var isUndefined = require('./isUndefined');
var _           = require('./collection');
var result      = require('./result');

module.exports = function (target) {

¶

Return a scoped function so each fork of a chain has its own working value This way, additional chains do not mutate the state of other chains.
```
  return function (value, scope) {
    var chain = {};
```

Returns a function that will execute a given method upon the value, reassigning `value if the result of the function is defined.

    var getChainable = function(method) {
      return function() {
        var args = _.toArray(arguments);

        args.unshift(value);

        var result = method.apply(scope, args);

        if (!isUndefined(result)) {
          value = result;
        }

        return chain;
      };
    };

¶

Extend the chain object with the members of the target. This process is similar to how ./collection.js is built however the returned result of each invocation is the chain itself.
```
    for (var d in target) {
      chain[d] = getChainable(target[d]);
    }
```

chain.valueOf allows the retrieval of the source value

    chain.valueOf = function() {
      return value;
    };

Allows the retrieval of a specific key in the source value with an optional fallback

    chain.get = function (key, fallback) {
      return result(value, key, fallback);
    };

    return chain;
  };

};