What is this?
vᴀꜱᴛly is a toolkit for handling expression ASTs (such as those produced by JSEP). These ASTs are a subset of ASTs produced by full-blown parsers like Esprima.
Intended to be used in conjunction with JSEP, but should work with any AST that conforms to the same structure.
Extracted from Mavo.
Features
- Zero dependencies
- Small footprint
- Works in Node and the browser
- Tree-shakeable
Usage
npm i vastly
Then you can use it either by importing the whole library:
import * as vastly from "vastly"; // or const vastly = require("vastly"); in CJS
import { parse } from "jsep";
const ast = parse("1 + x * y");
const result = vastly.evaluate(ast, {x: 2, y: 3});
or individual functions:
import { evaluate } from "vastly"; // or const { evaluate } = require("vastly"); in CJS
import { parse } from "jsep";
const ast = parse("1 + x * y");
const result = evaluate(ast, {x: 2, y: 3});
If you’re using vastly from a browser, without a bundler, fear not! You can just import from src directly:
import { evaluate } from "https://vastly.mavo.io/src/evaluate.js";
/* or */
import * as vastly from "https://vastly.mavo.io/src/index-fn.js";
/* or */
import { evaluate } from "https://vastly.mavo.io/dist/vastly.js";
/* or */
import * as vastly from "https://vastly.mavo.io/dist/vastly.js";