Creative Property Expression Parser/Evaluator

cpe-parser is a Javascript package for parsing and evaluating Creative Property Expressions (CPEs). CPEs are used to represent text strings that may embed dynamic data or perform simple arithmetic calculations.

The most common use case for CPEs is to templatize an otherwise static text string. Consider the following strings:

See other dresses like this.
See other shoes like this.
See other accessories like this.

If there is a dataset of similar products with categories, you might want to replace the category name above with a reference to that dataset using a CPE:

See other {{similarProducts[1].categoryName}} like this.

In the example CPE above, an embedded expression (surrounded by {{ and }}) references a dataset called similarProducts. When evaluated, it will be replaced with the categoryName attribute from the first item in the similarProducts dataset.

CPEs can also do simple arithmetic. For example:

{{deals[1].name}} expires in less than {{deals[1].lifetimeHours * 60}} minutes!

Installation

To install via NPM:

npm install --save cpe-parser

Usage

To evaluate a CPE:

var cpeParser = require('cpe-parser');

var result = cpeParser.evaluate.fromString('One plus two equals {{1 + 2}}.');

console.log(result);
// "One plus two equals 3."

Evaluating within an environment:

var env = {
  queries: {
    fruit: [
      { name: 'apple' },
      { name: 'banana' }
    ]
  }
};

var result = cpeParser.evaluate.fromString(
  'I love {{fruit[1].name}}s and {{fruit[2].name}}s!',
  env
);

console.log(result);
// "I love apples and bananas!"