JSFiddle - React, Tailwind, and code Playground

HTML

Code
<textarea id="code"></textarea>
<br/>
<button onclick="runcode()">Run</button>
<br/>Output:
<textarea id="output"></textarea>

JavaScript

$(function(){
    locals=[];
});
$('button').click(function () {
    var opsTable = [];
    opsTable['di'] = 'display';
    opsTable['dis'] = 'display';
    opsTable['disp'] = 'display';
    opsTable['displ'] = 'display';
    opsTable['displa'] = 'display';
    opsTable['display'] = 'display';
    opsTable['loc'] = 'local';
    opsTable['loca'] = 'local';
    opsTable['local'] = 'local';
    var code = $('#code').val();
    var commands = code.split('\n');
    var tokens = [];
    commands.forEach(function (entry) {
        tokens.push(entry.split(' '));
    });
    var error = '';
    $.each(tokens,function (index,entry) {
        var tok = entry[0];
        entry[0] = opsTable[tok];
        if (entry[0] === undefined) {
            error = tok + ' is not a recognized command';
            outputError(error);
            return false;
        }
        if(!execute(entry)){
            return false;
        }
    });
});

function execute(command){
    switch(command[0]){
        case 'display':
            return executeDisplay(command);
        case 'local':
            return executeLocal(command);
    }
}

function executeLocal(command){
    var parts=command[1].split('=');
    locals[evaluate(parts[1])]=evaluate(parts[2]);
    return true;
}

function executeDisplay(command){
    for(var i=1;i<command.length;i++){
        var comVal=command[i];
        $('#output').val(function(ind,val){
            return val+evaluate(command[i])+'\n';
        });
    }
    return true;
}

function evaluate(str){
    return str;
}

function outputError(error) {
    $('#output').val(error);
}