Introduction to jsinq

jsinq is a powerful JavaScript library that brings SQL-like query capabilities to JavaScript. It allows you to perform complex data manipulations and queries efficiently over arrays and other enumerable data structures. By using jsinq, developers can write clean, readable, and maintainable code when handling collections of data.

Useful jsinq API Examples

1. Initializing a Query

  // Initialize a query
  var query = new jsinq.Query()
    .from(data_array);

2. Selecting Data

  // Select specific fields
  var names = new jsinq.Query()
    .from(data_array)
    .select(function (item) { return item.name; })
    .execute();

3. Filtering Data

  // Filter using where clause
  var filtered = new jsinq.Query()
    .from(data_array)
    .where(function (item) { return item.age > 30; })
    .execute();

4. Grouping Data

  // Group items by a field
  var groupedByCountry = new jsinq.Query()
    .from(data_array)
    .groupBy(function (item) { return item.country; })
    .execute();

5. Joining Data

  // Join two data sets
  var joined = new jsinq.Query()
    .from(people)
    .join(countries, 
        function(person) { return person.countryId; }, 
        function(country) { return country.id; }, 
        function(person, country) { return { person: person.name, country: country.name }; })
    .execute();

6. Ordering Data

  // Order by a specific field
  var ordered = new jsinq.Query()
    .from(data_array)
    .orderBy(function (item) { return item.name; })
    .execute();

7. Using Aggregates

  // Applying aggregates like sum, count, and average
  var totalAge = new jsinq.Query()
    .from(data_array)
    .sum(function (item) { return item.age; })
    .execute();
  
  var averageAge = new jsinq.Query()
    .from(data_array)
    .average(function (item) { return item.age; })
    .execute();

  var itemCount = new jsinq.Query()
    .from(data_array)
    .count()
    .execute();

Example Application Using jsinq

  var items = [
    { name: 'John', age: 25, country: 'USA' },
    { name: 'Jane', age: 30, country: 'UK' },
    { name: 'Jack', age: 35, country: 'Canada' },
    { name: 'Jill', age: 28, country: 'Australia' }
  ];
  
  var countryGroups = new jsinq.Query()
    .from(items)
    .groupBy(function (item) { return item.country; })
    .select(function (group) {
      return {
        country: group.key,
        members: group.elements
      };
    })
    .execute();
  
  console.log(countryGroups);

  /* Expected Output
  [
    { country: 'USA', members: [ { name: 'John', age: 25, country: 'USA' } ] },
    { country: 'UK', members: [ { name: 'Jane', age: 30, country: 'UK' } ] },
    { country: 'Canada', members: [ { name: 'Jack', age: 35, country: 'Canada' } ] },
    { country: 'Australia', members: [ { name: 'Jill', age: 28, country: 'Australia' } ] }
  ]
  */

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