Mgoqueryjs NPM

mgoquery.js

A simple query language that returns a valid MongoDB query. It is meant to be much easier to use than MongoDB queries. Furthermore it is shorter and more convenient to standard logic notations. The parser ignores all whitespaces except for that inside of delimiters.

Installation

npm install --save mgoqueryjs

Usage

var Mgoquery = require('mgoqueryjs');
var mgoquery = new Mgoquery();

console.log(mgoquery.parseSync("x='3'"));

This should output: {'x': '3'}

Or use the asynchronous version that supports both the callback (error-first-style)- and the promise-pattern:

mgoquery.parseAsync("x='3'").then(function(str){
    console.log(str);
})

mgoquery.parseAsync("x='3'", function(err, str){
    console.log(str);
})

Changes in 0.2.0

The parse function is still supported but it is recommended to switch to the new parseSync/parseAsync functions to avoid confusing behavior like:

var i = 0;

mgoquery.parse("x='3'", function(str){
    i++;
});

console.log(i); //output: 1

In this case the parse function seems to work asynchronous but has synchronous behavior.

Expression

Expressions consist of a field, an operator and a value. Currently there are four types of operators available: "=" (equals), "<" (less-than), ">" (higher-than) or "^" (regular expression).

Examples:

x='3' becomes {'x': '3'}
foo > '4' becomes {'foo': {'$gte': '4'}}
y < 'x' becomes {'y': {'$lte': 'x'}}
y ^ '^-?\d{1,19}$' becomes {'y': {'$regex': '^-?\d{1,19}$'}}

Changes in 0.2.0

Expressions do now support integers and boolean values. For example:

x=2 => {'x': 2}
x>2 => {'x': {'$gte': 2}}
x='2' => {'x': '2'}
x=true => {'x': true}
x=false => {'x': false}

Combined expressions

Expressions can be combined using "," (and) or "|" (or).

Examples:

x='1' , y='2' becomes {'$and': {'x': '1'}, {'y': '2'}}
x='1' | y='2' becomes {'$or': {'x': '1'}, {'y': '2'}}

As long as you use only one operator you can combine as much expressions as you want.

Example:

x='1' , y='2' , x='3', x='3' becomes {'$and': {'x': '1'}, {'y': '2'}, {'x': '3'}, {'x': '3'}}

Group

It is not possible to combine multiple expressions by using both "," and "|". The parser cannot determine the order in which the expressions should be evaluated. Groups can be used to describe that order. You can specify groups by using brackets.

Examples:

(x>'1', x<'5') | (y>'2', x='None') becomes {'$or': [{'$and': {'x': {'$gte': '1'}}, {'x': {'$lte': '5'}}}, {'$and': {'y': {'$gte': '2'}}, {'x': 'None'}}]}
(x>'1', x<'5') , (y>'2', x='None') becomes {'$and': [{'$and': {'x': {'$gte': '1'}}, {'x': {'$lte': '5'}}}, {'$and': {'y': {'$gte': '2'}}, {'x': 'None'}}]}

At these examples you can see how much shorter this query language is.

Combined Groups

Similar to expressions you can combine a much amount of groups as long as you use only one operator. Examples:

(x='1', x<'1') | (y='2') | (z='3') becomes {'$or': [{'$and': {'x': '1'}, {'x': {'$lte': '1'}}}, {'y': '2'}, {'z': '3'}]}
(x='1', x<'1'), (y='2'), (z='3') becomes {'$and': [{'$and': {'x': '1'}, {'x': {'$lte': '1'}}}, {'y': '2'}, {'z': '3'}]}