Evaluatable

Evaluatable is a javascript module for evaluating deeply nested JSON objects. The key idea of which is to use key paths to get either single values of value arrays from an object. These values can then be compared using built-in operators.

Using the Evaluatable module

Using Evaluatable is as easy as inititalizing a new Evaluatable object using the target object.

In the browser

<script type="text/javascript" src="evaluatable.js"></script>

<script type="text/javascript">
  (function() {

    // Initialize here

  })();
</script>

In Node JS

Evaluatable = require("evaluatable")

Initializing an Enumerable Object

  evaluatableObject = {
    name: "foo",
    number: 1,
    date: Date.parse('2012-12-21'),
    jsonDate: "2012-12-21T00:00:00.000Z",
    baz: {
      name: "fooBaz"
    },
    bars: [
      {
        name: "bar1",
        number: 1,
        date: Date.parse('2012-12-20'),
        jsonDate: "2012-12-20T00:00:00.000Z"
      }, {
        name: "bar2",
        number: 2,
        date: Date.parse('2012-12-22'),
        jsonDate: "2012-12-22T00:00:00.000Z"
      }
    ]
  };

  e = new Evaluatable(evaluatableObject);

Getting values Using Key Paths

Accessing values via key path is simple. Using the object outlined in the example above:

  e.valueForKeyPath("name");
  >> "foo"

  e.valueForKeyPath("baz.name")
  >> "fooBaz"

Values in nested arrays or children of arrays will return a flattened array with all values matching the key path

  e.valueForKeyPath("bars.name")
  >> ["bar1", "bar2"])

Using Built-in Operators

In order to provide a few simple built-in operators the Evaluatable module contains several built-in operators that can be used as part of the evaluate method.

is

e.evaluate("one", "is", "one");
>> true

e.evaluate(1, "is", 1)
>> true

evaluations will even attempt to reconcile type differences for you

e.evaluate(1, "is", "1")
>> true

isnt

e.evaluate("one", "isnt", "two");
>> true

e.evaluate(1, "isnt", 1)
>> true

isGreaterThan

e.evaluate("b", "isGreaterThan", "a")
>> true

e.evaluate(2, "isGreaterThan", 1)
>> true

date = new Date()
date2 = date.getTime() + (3600 * 24 * 1000)
e.evaluate(date2, "isGreaterThan", date)
>> true

isLessThan

e.evaluate("a", "isLessThan", "b")
>> true

e.evaluate(1, "isLessThan", 2)
>> true

date = new Date()
date2 = date.getTime() + (3600 * 24 * 1000)
e.evaluate(date, "isLessThan", date2)
>> true

startsWith

e.evaluate("baz", "startsWith", "b")
>> true

e.evaluate(21, "startsWith", 2)
>> true

For arrays, startsWith checks whether the first element of the array matches to the target value.

e.evaluate(["1", "2", "3"], "startsWith", "1")
>> true

contains

e.evaluate("baz", "contains", "a")
>> true

e.evaluate(213, "contains", 1)
>> true

For arrays, contains checks whether the any element of the array matches to the target value.

e.evaluate(["1", "2", "3"], "contains", "1")
>> true

Evaluting Using Key Paths

Evaluations can also be performed using key paths.

e.evaluateKeyPath("name", "is", "foo")
>> true

e.evaluateKeyPath("date", "isAfter", new Date())  
>> true

e.evaluateKeyPath("jsonDate", "isAfter", new Date())
>> true

Evaluting Using Aggregators

Aggregations can eiher use built-in aggregation functions or can extend the keypath using the 'keypath:aggregator' format. The following aggregators are currently supported

any

e.any("bars.name", "is", "bar1"))
>> true

e.evaluateKeyPath("bars.name:any", "is", "bar1"))
>> true

all

e.all("bars.name", "startsWith", "bar"))
>> true

e.evaluateKeyPath("bars.name:all", "startsWith", "bar"))
>> true

none

e.none("bars.name", "is", "bar3"))
>> true

e.evaluateKeyPath("bars.name:none", "is", "bar3"))
>> true

sum

e.sum("bars.number", "is", 3))
>> true

e.evaluateKeyPath("bars.number:sum", "is", 3))
>> true

min

e.min("bars.number", "is", 1))
>> true

e.evaluateKeyPath("bars.number:min", "is", 1))
>> true

max

e.max("bars.number", "is", 2))
>> true

e.evaluateKeyPath("bars.number:max", "is", 2))
>> true

count

e.count("bars", "is", 2))
>> true

e.evaluateKeyPath("bars:count", "is", 2))
>> true

average

e.average("bars.number", "is", 1.5))
>> true

e.evaluateKeyPath("bars.number:average", "is", 1.5))
>> true

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