contrib/wally_js_example.html

<!doctype html>
<html lang="en-us">
    <head>
        <meta charset="utf-8">
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <title>Wallycore JS Example</title>
        <style>
            textarea { font-family: monospace; width: 80%; padding-right: 0; margin-left: auto; margin-right: auto; display: block; }
        </style>
    </head>
    <link rel="icon" href="data:,">
    <body>
        <textarea id="output" rows="16"></textarea>
        <script type='text/javascript'>
            var element = document.getElementById('output');
            var wally_example = function() {
                const as_utf8 = function(ptr) { return Module.UTF8ToString(Module.getValue(ptr, '*')); };
                const b2h = function(buf) { return Array.prototype.map.call(buf, x => ('00' + x.toString(16)).slice(-2)).join(''); };
                const wally_init = Module.cwrap("wally_init", ['number'], ['number']);
                const wally_secp_randomize = Module.cwrap("wally_secp_randomize", ['number'], ['array', 'number']);
                const bip39_mnemonic_from_bytes = Module.cwrap('bip39_mnemonic_from_bytes', ['number'], ['number', 'array', 'number', 'number']);
                const wally_free_string = Module.cwrap('wally_free_string', ['number'], ['number']);

                // Initialize wally
                var text = "init: " + wally_init(0) + '\n';
                var entropy = new Uint8Array(32); // WALLY_SECP_RANDOMIZE_LEN
                window.crypto.getRandomValues(entropy);
                text = text + "secp_randomize: " + wally_secp_randomize(entropy, entropy.length) + '\n';

                // Create a BIP39 seed
                var seed = new Uint8Array(16); // BIP39_ENTROPY_LEN_128
                window.crypto.getRandomValues(seed);
                text += "seed: " + b2h(seed) + '\n';

                // Generate a mnemonic from it
                var ptr = Module._malloc(4); // Holds our output pointer
                var ret = bip39_mnemonic_from_bytes(null, seed, seed.length, ptr);
                const mnemonic = as_utf8(ptr);
                text = text + "mnemonic: " + mnemonic + '\n';
                wally_free_string(Module.getValue(ptr, '*'));
                Module._free(ptr);

                // Display our output
                element.value = text;
            }
            var Module = {
                preRun: [],
                postRun: [wally_example],
            };
        </script>
        <script type="module">
            import InitWally from "./wallycore.js";
            InitWally(Module);
        </script>
    </body>
</html>