geton

A template engine for extracting and transforming data, designed by Shuo Feng.

Table of Contents

• Introduction
• Features
• Installation
• Usage
• API Reference
• License

Introduction

This lightweight library provides a template engine designed for TypeScript and JavaScript applications, offering customizable capabilities for data extraction and transformation.

Installation

yarn add geton

Or

npm install geton

Usage

import { get } from "geton";

// Example data with nested objects and arrays
const context = {
  user: {
    name: "Shuo Feng",
    locations: [
      {
        city: "Beijing",
        country: "China",
      },
      {
        city: "Los Angeles",
        country: "United States",
      },
    ],
  },
};

// Basic property access
console.log("Name:", get("user.name", context));
// Output: "Shuo Feng"

// Access array
console.log("Locations:", get("user.locations", context));
// Output: [{"city":"Beijing","country":"China"},{"city":"Los Angeles","country":"United States"}]

// Access array element by index
console.log("Locations[0]:", get("user.locations.0", context));
// Output: {"city":"Beijing","country":"China"}

// Access nested property in array element
console.log("Locations[0].city:", get("user.locations.0.city", context));
// Output: "Beijing"

// Extract list of specific properties from array
console.log("List of cities:", get("list(user.locations, 'city')", context));
// Output: ["Beijing","Los Angeles"]

// Concatenate array values into a string
console.log(
  "String of cities:",
  get("concat(list(user.locations, 'city'))", context)
);
// Output: "Beijing,Los Angeles"

API Reference

get(template: string, context: TemplateContext, handlers?: HandlerMap): unknown

The core function for extracting and transforming data based on a template string.

| Parameter | Type | Description | | ---------- | ----------------- | ------------------------------------------------ | | template | string | A string template with expressions and handlers | | context | TemplateContext | The data context to extract from | | handlers | HandlerMap | Optional custom handlers for data transformation |

Default Handlers

| Handler | Description | | --------------- | ---------------------------------------------- | | concat | Concatenates multiple values with commas | | upper | Converts a string to uppercase | | lower | Converts a string to lowercase | | replace | Replaces first occurrence of a substring | | replaceAll | Replaces all occurrences of a substring | | jsonParse | Parses a JSON string | | jsonStringify | Stringifies a JSON object | | list | Extracts a property from each item in an array |

License

This library is MIT licensed.