node-logic-filter-strings

A parser that transforms logical expression strings for filtering JSON objects into their equivalent logic filter structure.

Example

var logicFilterString = require('logic-filter-strings');

var obj = logicFilterString('foo === "bar"&&bar === "baz qux"');

Obj will be:

[['foo', '===', 'bar'], '&&', ['bar', '===', 'baz qux']]

Filter Language

This interpreter was desgined with the end goal of being able to provide rules for filtering JSON object streams. It was meant to be used by node-logic-filter as the means of parsing filter rules. In general, strings on the left side of an equality represent keys in an object, and strings/numbers/arrays/objects on the right side of an equality represent values to compare against. You are also able to use &&, ||, and ! to combine conditions/expressions as you might expect.

Case: foo exists in the comparison object

'foo'

Case: foo does not exist in the comparison object

'!foo'

Case: foo equals string

'foo === "bar"'

Note: The quotes around "bar" are required

Case: foo equals array

'foo === [1, 2, 3]'

Case: foo equals object

'foo === {bar: "baz"}'

Case: foo equals string and bar equals string

'foo == "baz" && bar == "qux"'

Note: == and === are interchangeable

Case: foo does not equal string

'foo !== "baz"'

Case: field on a nested object equals string

'foo.bar.qux === "baz"'

Case: Or-ing 3 or more conditions

'(foo == "baz" || bar == "qux") || a === "b"'

Note: Parentheses are necessary