Interpolate

Simple template string interpolation for strings and files

Features:

• Easy to use
• Interpolate template strings: {{VAR}}
• Parses strings and files
• Can interpolate from parameters and/or environment variables
• Supports nested paths from complex parameters
• Includes cli tool and node api

About

We needed a way to interpolate template variables from strings and files at build and/or run time. I wanted both a node api and cli tool to use for easy integration with jenkins, docker, or kubernetes, and also wanted the ability to interpolate with environment variables or manually specified parameters.

Usage

Add interpolate as a dependency for your app and install via npm

npm install @danmasta/interpolate --save

Require the package in your app

const interpolate = require('@danmasta/interpolate');

Options

name | alias | type | description -----|-------|------|------------ input | i | string | Directory or file path to use when reading files. Default is undefined output | o | string | Directory to write parsed files to. Default is undefined src | | string | Glob pattern string to filter input file list, ex: **/*.yml. Default is undefined string | s | string | Text string to parse. Default is undefined stdin | - | boolean | Read input from stdin. Default is false env | e | boolean | If true will also interpolate with environment variables. Default is false params | p | object\|string | Object of key,value pairs to use for parameter matching. If string, it should either be a stringified json object, or a comma-separated key,value list: "key1=1,key2=2". Default is undefined warn | w | boolean | If true will write a message to stderr when a parameter is not found. Default is true throw | t | boolean | If true will throw an error when a parameter is not found. Default is false default | d | string | Default value to use when a parameter is not found. Default is '' replaceMissing | r | string | If false will not replace variables that are undefined. Default is false format | f | string | Enables or disables formatter functions. Default is true delimiter | | string | What delimiter to use for parsing formatter names. Default is '\|' help | h | boolean | View the cli help menu

Methods

Name | Description -----|------------ parse(str, opts) | Parses a string with optional opts file({ input, output, src }) | Parses a file or directory based on opts.input. Files are parsed then written to opts.output

Envstr

This package includes an extra cli utility called envstr. It formats json or table style data into key=val pairs that can be easily consumed in bash scripts or exported as environment variables.

Options

name | alias | type | description -----|-------|------|------------ string | s | string | Text string to parse. Default is undefined stdin | - | boolean | Read input from stdin. Default is undefined json | j | boolean | Handle input as json. Default is false key | k | string | If input is json, parse data at specified key. Default is undefined quotes | q | boolean | If true add quotes around env values. Default is false newline | n | string | Which character to use as newline delimeter. Default is '\n' include | i | string | Which keys to include in output: key1,key2 exclude | e | string | Which keys to exclude from output: key3,key4 caps | c | string | If true capitalizes the output key name. Default is false export | x | string | If true adds the 'export' keyword in front of each output key. Default is false help | h | boolean | View the cli help menu

Examples

Parse a text string

let params = {
    SRC: './src',
    BUILD: './build'
};

let str = 'input: {{SRC}} -> output: {{BUILD}}';

console.log(interpolate(str, { params }));

Parse a directory of files via cli

interpolate --env -i deploy -o build/deploy --src **/*.(yml|yaml)

Convert json data to env str format

envstr -s '{"KEY1":true,"KEY2":false}' --json --quotes

Testing

Tests are currently run using mocha and chai. To execute tests run npm run test. To generate unit test coverage reports run npm run coverage

Contact

If you have any questions feel free to get in touch