Data Aggregator Language

Execute aggregation expressions on a given data set.

What it Does

Given the following input data structure,
``js
const input = [{
date: '2017-09-16',
reservations: {
silver: 12,
gold: 5
},
customers: ['brad']
}, {
date: '2017-09-17',
reservations: {
silver: 3,
gold: 2
},
customers: ['angelina']
}]
`
the parser allows mixing aggregation expressions over the input with common arithmetic operators.

For example,
* an aggregation expression: SUM reservations.silver would yield 12 + 3 = 15.
* an aggregation expression mixed with arithmetic: SUM reservations.silver + 3 would yield (12 + 3) + 3 = 18


Usage


`js
const aggregator = require('@emartech/data-aggregator-language')(input);
const result = aggregator('SUM reservations.silver')
`

Supported Syntax in Aggregation Expressions

Examples below are for the input defined above.

$3

#### Constants
* LENGTH
* LENGTH (yields 2)
* LENGTH + 3 (yields 5)
* Any number literal
* 5 (yields 5)

#### Unary Operators
* SUM
* SUM reservations.silver (yields 15)
* LAST
* LAST reservations.silver (yields 3)
* AVERAGE
* AVERAGE reservations.silver (yields 7.5)

#### Binary Operators
+, -, *, /
For example, (LAST reservations.silver + 3) * 2 / 2 (yields 6)




$3


* UNION
* UNION customers (yields ['brad', 'angelina'])

$3

* EMPTY
* EMPTY UNION customers (yields false)
* NOT
* NOT EMPTY UNION customers (yields true)




Using with Webpack

Because of the way the underlying Chevrotain library is implemented, name mangling
interferes with the parser's operation. To resolve this issue, webpacked host projects need to disable name mangling for the token names used in this grammar.

To help with this, the module exports these names in a tokens array.

To configure webpack, include the following in your webpack.config.js:
`js
const { tokens } = require('@emartech/data-aggregator-language');


module.exports.optimization = {
minimizer: [
new UglifyJsPlugin({
uglifyOptions: {
mangle: {
reserved: tokens
}
}
})
]
};
``

Commit Convention

Semantic release depends on the Angular commit message conventions. Please follow these.

Requirements

See package.json for required libraries and versions.

Credit

Uses SAP/chevrotain for parsing.

Contributing

This project is open to feature requests/suggestions, bug reports etc. via GitHub issues. Contribution and feedback are encouraged and always welcome. For more information about how to contribute, the project structure, as well as additional contribution information, see our Contribution Guidelines.

How to Obtain Support

This software is provided as-is.

Code of Conduct

We as members, contributors, and leaders pledge to make participation in our community a harassment-free experience for everyone. By participating in this project, you agree to abide by its Code of Conduct at all times.

Licensing

Copyright 2018-2023 SAP SE or an SAP affiliate company and data-aggregator-language contributors. Please see our LICENSE for copyright and license information. Detailed information including third-party components and their licensing/copyright information is available via the REUSE tool