WebAssembly

    For host environments like the web browser and nodejs, build as a dynamic library using the freestanding OS target. Here’s an example of running Zig code compiled to WebAssembly with nodejs.

    test.js

    1. const fs = require('fs');
    2. const source = fs.readFileSync("./math.wasm");
    3. const typedArray = new Uint8Array(source);
    5. WebAssembly.instantiate(typedArray, {
    6.   env: {
    7.     print: (result) => { console.log(`The result is ${result}`); }
    8.   }}).then(result => {
    9.   const add = result.instance.exports.add;
    10.   add(1, 2);
    11. });

    WASI

    args.zig

    3.     var general_purpose_allocator = std.heap.GeneralPurposeAllocator(.{}){};
    4.     const gpa = &general_purpose_allocator.allocator;
    5.     const args = try std.process.argsAlloc(gpa);
    6.     defer std.process.argsFree(gpa, args);
    8.     for (args) |arg, i| {
    9.         std.debug.print("{}: {s}\n", .{ i, arg });
    10.     }
    11. }
    1. $ zig build-exe args.zig -target wasm32-wasi

    preopens.zig

    1. const std = @import("std");
    2. const PreopenList = std.fs.wasi.PreopenList;
    3. pub fn main() !void {
    4.     var general_purpose_allocator = std.heap.GeneralPurposeAllocator(.{}){};
    5.     const gpa = &general_purpose_allocator.allocator;
    7.     var preopens = PreopenList.init(gpa);
    8.     defer preopens.deinit();
    10.     try preopens.populate();
    12.     for (preopens.asSlice()) |preopen, i| {
    13.         std.debug.print("{}: {}\n", .{ i, preopen });
    14.     }
    15. }