JSFiddle - React, Tailwind, and code Playground

HTML

<pre id='results'></pre>
<hr/>
<pre id='details'></pre>

JavaScript

// Generate some random data ... 
var data = new Array();
for (var i = 0; i < 100000; i ++) { 
    data[i] = Math.floor(Math.random()*65536); // 16 bits
    data[i] *= Math.floor(Math.random()*65536); // 32 bits
    data[i] *= Math.floor(Math.random()*65536*16); // 52 bits
    
    //$('#results').append(data[i].toString(16)+"\n");
}

function test(data, testFn) { 
    var newData = new Array(); 
    var start = new Date();
    
    for (i = 0; i < data.length; i ++) { 
        newData[i] = testFn(data[i]);
        /* test output 
        $('#details').append(testFn.name + " : "+data[i].toString(16)+
                             " -> "+newData[i].hi.toString(16)+" , "+
                             newData[i].lo.toString(16)+" \n");
        end test output */
    }
    var end = new Date();
    $('#results').append("Function: "+testFn.name+" completed in "+(end-start)+" ms\n");
}


function numeric(n) {
    return { 
        hi: Math.floor(n / 4294967296), 
        lo: (n & 0xFFFFFFFF) >>> 0
    }
}

function strings(n) { 
    s = n.toString(16);
  
    if (s.length > 8) { 
        
        return { 
            hi: parseInt( s.toString(16).slice(0, s.length - 8), 16),
            lo: parseInt( s.toString(16).slice(s.length - 8), 16)
        }
    } else { 
        return { hi: 0, lo: n } 
    }

}

function stringPadNoParse(n) { 
    s = "00000000000"+n.toString(16);
    return { 
        hi: s.toString(16).slice(0, s.length - 8), 
        lo: s.toString(16).slice(s.length - 8)
    }
}
        

function stringPad(n) { 
    s = "00000000000"+n.toString(16);
    return { 
        hi: parseInt( s.toString(16).slice(0, s.length - 8), 16),
        lo: parseInt( s.toString(16).slice(s.length - 8), 16)
    }
}

n = strings(4294967296);
 $('#results').append(n);
//test(data, numeric);
//test(data, strings);
//test(data, stringPad);                         
//test(data, stringPadNoParse);                         
//$('#results').append("DONE!\n");