odata-query-maker v1.0.0

OData Query Maker

A typescript library to make OData queries.

Inspirations

This library was made based in the following libraries: ngx-odata , odata-query-builder and odata-form-builder . It was taken parts of both and mixed. The goal is to do something diferent, but not start from the scratch.

Operators

There is two types of operators: comparison and string. The comparison operators are Equal, Less, Greater, LessOrEqual,GreaterOrEqual, NotEqual. The string operators are Contains, StartsWith, EndsWith.

Functions

To each option in OData there is a function in this library with the same name. The function count no need parameter. The functions skip and top need a number. To sort ascending use orderBy function with the field as parameter and the orderByDesc function is used to sort descendent.

The function select need an array of the fields. The expand needs the field to expand and will open a predicate for do a query. At least, the filter function use internal functions to create conditions.

Examples

To exemplify, lets create some classes.

export class Employee {
    name: string;
    salary: number;
    age: number;
    departament: Departament;
}

export class Departament {
    name: string;
}

Create the object tha will build your query

let odataQueryMaker = new OdataQueryMaker<Employee>();

You can filter using comparison operator.

let query1 = odataQueryMaker
    .filter(f => f.valueFilter(e => e.salary, ComparisonOperator.Equals, 5000))
    .generate();

The value of query1 will be $filter=salary eq 5000.

You can filter using string operators.

let query2 = odataQueryMaker
    .filter(f => f.stringFilter(e => e.name, StringOperator.Contains, 'Will'))
    .generate();

The value of query2 will be $filter=contains(name, 'Will').

If the value is null, by standart the filter will ignore the condition.

let query3 = odataQueryMaker
    .filter(f => f.valueFilter(e => e.age, ComparisonOperator.Equal, null))
    .generate();

The value of query3 will be empty. If the null value must exist, define in the options on the constructor method like:

let odataQueryOptions = {ignoreNull: false};
let odataQueryMakerNotIgnoreNull = new OdataQueryMaker<Employee>(odataQueryOptions);

Then, the same query will return $filter=age eq null.

To add logical operators use the functions and() and or().

let query4 = odataQueryMaker
    .filter(f => f.valueFilter(e => e.salary, ComparisonOperator.Equal, 5000).and()
                    .stringFilter(e => e.name, StringOperator.Contains, 'Will'))
    .generate();

The value of query4 will be $filter=salary eq 5000 and contains(name, 'Will').

If some value is null, the filter will ignore the condition.

let query5 = odataQueryMaker
    .filter(f => f.valueFilter(e => e.age, ComparisonOperator.Equal, null).and()
                    .stringFilter(e => e.name, StringOperator.Contains, 'Will'))
    .generate();

The value of query5 will be $filter=contains(name, 'Will').

You can add a inner filter (that will generate filter with parentesis).

let query6 = odataQueryMaker
    .filter(f => f.stringFilter(e => e.name, StringOperator.Contains, 'Will')
                  .andFilter(f2 => f2.valueFilter(e => e.salary, ComparisonOperator.Greater, 5000).or()
                                     .stringFilter(e => e.departament.name, StringOperator.StartsWith, 'Sales')))
    .generate();

The value of query6 will be $filter=contains(name, 'Will') and (salary gt 5000 or startswith(departament/name, 'Sales')).

If the inner condition is null, both it and its logical operator will be ignored.

let query7 = odataQueryMaker
    .filter(f => f.stringFilter(e => e.name, StringOperator.Contains, 'Will')
                      .andFilter(f2 => f2.and().valueFilter('age', ComparisonOperator.Greater, null).or()))
    .generate();

The value of query7 will be $filter=contains(name, 'Will').

The example below shows how to use select, skip, top, orderBy, orderByDesc.

let query8 = odataQueryMaker
    .select(e => e.name, e => departament.name)
    .skip(1)
    .top(5)
    .orderBy(e => salary)
    .orderByDesc(e => age);
    .generate();

The value of query8 will be $top=5&$skip=1&$orderby=salary asc,age desc&$select=name,departament/name.

The example below shows how to use count associate with a filter.

let query9 = odataQueryMaker
    .filter(f => f.stringFilter(e => e.name, StringOperator.Contains, 'Will'))
    .count()
    .generate();

The value of query9 will be $count=true&$filter=contains(name, 'Will')'.

The example below shows how to use expand associate with a count.

let query10 = odataQueryMaker
    .expand(e => e.departament, dep => dep.count())
    .generate();

The value of query10 will be $expand=departament($count=true).