SelectQL.js

SelectQL.js is inspired by Structured Query Language (SQL) for accessing and manipulating Objects in an easy and familiar way. It supports complex Objects and Arrays using Builder Design Pattern.

Install

npm install selectql.js --save

Usage

You may use Arrays like Objects to select and manipulate in well known SQL like syntax that uses builder patterns.

First include the library by node provided require keyword like: const { SelectQL, Operators } = require('selectql.js');

Client array like object, make sure to follow the syntax of banana in the box [{}] syntactic sugar:

let cities = [
  { name: 'Los Angeles', population: 3792621, winner: 5 },
  { name: 'New York', population: 8175133, winner: 4 },
  { name: 'Chicago', population: 2695598, winner: 8 },
  { name: 'Houston', population: 2099451, winner: 9 },
  { name: 'Philadelphia', population: 1526006, winner: 1 },
];

//Default object to be returned in case empty or null result.
let denver = [{ name: 'Denver', population: 715522, winner: 8 }];

Enum should be followed in order to properly chain the functions.

Operator	Value
EQUAL	==
NOT_EQUAL	!=
GREATER_THAN	>
GREATER_EQUAL	>=
LESS_THEN	<
LESS_THEN_EQUAL	<=

enum Operators {
        EQUAL = '==',
        NOT_EQUAL = '!=',
        GREATER_THAN = '>',
        GREATER_EQUAL = '>=',
        LESS_THEN = '<',
        LESS_THEN_EQUAL = '<=',
}

Initialize the library by providing the objects of array and chain through the provided APIs

let selectQl = new SelectQL(cities)
  .where('name', Operators.NOT_EQUAL, 'New York') // Will filter to make sure 'New York' should filtered
  .and('population', Operators.LESS_THEN, '5526006') // Will filtered the population less than 5526006
  .and('winner', Operators.GREATER_EQUAL, 15) // will only return if winner value more than 15
  .ifEmptyThen(denver) // if everything is empty, client can provide default object like array
  .build();
  
  console.log(selectQl, 'sq'); // Will returned denver array

Working DEMO: https://typescript-a3w8i1.stackblitz.io

Client Chainable APIs:

• where(key: any, operator: Operators, value: any): As per SQL definition The WHERE clause is used to filter records. It is used to extract only those records that fulfill a specified condition. (this can be used multiple time) .where('name', Operators.NOT_EQUAL, 'New York')
• and(key: any, operator: Operators, value: any): where like function a predicate which will eventually use WHERE method (this can be used multiple time). .and('population', Operators.LESS_THEN, '5526006')
• join(concatWith: any): Client can provide object like array to concat with the originally provided array. .join(denver)
• ifEmptyThen(input: any): if no condition met or null then client can return it's own input/object .ifEmptyThen(denver)
• build(): builder function which is a must in order to return properly filtered array. .build()

License

Free Library!