Execute aggregation expressions on a given data set.
npm install @emartech/data-aggregator-languageExecute aggregation expressions on a given data set.
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
}
}
})
]
};
``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.
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