expression.md

Expression

The expression service parses Litespeed.js template syntax.

The main use for this service is to bind service value into views and view components like 'data-ls-echo' and 'data-ls-if' rely on it heavily.

The expression parser detects service path references, evaluate them and parses the final results.

Litespeed.js expression also supports 'mustache' or 'twig' like filters to give a lot more flexibility and power.

API

• parse(string)

parse()

Parses a Litespeed.js expression.

Param	Type	Description
string	string	Expression string. Use {{object.path}} to evaluate a service path or add a pipe to apply a filter {{object.path
def	string	Default value to use when expression has evaluated with empty result (optional)

Return Value

Resulted expression string or def parameter value if empty result.

Example

conatiner.set('user', {
    'name': 'john doe',
    'email': 'john@example.com'
}, true, true);

filter.add('uppercase', function (value) {
    return value.toUpperCase();
});

let name = expression.parse('hello {{user.name|uppercase}}'); // hello JOHN DOE
let empty = expression.parse('your age is {{user.age|uppercase}}', 30); // your age is 30