var crypto = require( 'crypto' )
var sha256 = s => {
    if ( typeof s == "string" ) s = new TextEncoder().encode( s );
    return crypto.subtle.digest( 'SHA-256', s ).then( hashBuffer => {
        var hashArray = Array.from( new Uint8Array( hashBuffer ) );
        var hashHex = hashArray
            .map( bytes => bytes.toString( 16 ).padStart( 2, '0' ) )
            .join( '' );
        return hashHex;
    });
}

var i = 0;
var hasher = async () => {
    var hash = await sha256( `test ${i}` );
    i = i + 1;
    if ( String( i ).endsWith( "00000" ) ) console.log( i );
    if ( i < 1000000 ) hasher();
}
hasher();