Anything-to-Number Conversion Table

I found this on StackOverflow by georg.

x parseInt(x) parseFloat(x) Number(x) +x ~~x x>>>0 isNaN(x)
"123" 123 123 123 123 123 123 false
"+123" 123 123 123 123 123 123 false
"-123" -123 -123 -123 -123 -123 4294967173 false
"123.45" 123 123.45 123.45 123.45 123 123 false
"-123.45" -123 -123.45 -123.45 -123.45 -123 4294967173 false
"12e5" 12 1200000 1200000 1200000 1200000 1200000 false
"12e-5" 12 0.00012 0.00012 0.00012 0 0 false
"0123" 123 123 123 123 123 123 false
"0000123" 123 123 123 123 123 123 false
"0b111" 0 0 7 7 7 7 false
"0o10" 0 0 8 8 8 8 false
"0xBABE" 47806 0 47806 47806 47806 47806 false
"4294967295" 4294967295 4294967295 4294967295 4294967295 -1 4294967295 false
"123456789012345678" 123456789012345680 123456789012345680 123456789012345680 123456789012345680 -1506741424 2788225872 false
"12e999" 12 Infinity Infinity Infinity 0 0 false
"" NaN NaN 0 0 0 0 false
"123foo" 123 123 NaN NaN 0 0 true
"123.45foo" 123 123.45 NaN NaN 0 0 true
" 123 " 123 123 123 123 123 123 false
"foo" NaN NaN NaN NaN 0 0 true
"12e" 12 12 NaN NaN 0 0 true
"0b567" 0 0 NaN NaN 0 0 true
"0o999" 0 0 NaN NaN 0 0 true
"0xFUZZ" 15 0 NaN NaN 0 0 true
"+0" 0 0 0 0 0 0 false
"-0" 0 0 0 0 0 0 false
"Infinity" NaN Infinity Infinity Infinity 0 0 false
"+Infinity" NaN Infinity Infinity Infinity 0 0 false
"-Infinity" NaN -Infinity -Infinity -Infinity 0 0 false
BigInt(1) 1 1 1 Error 1 Error Error
null NaN NaN 0 0 0 0 false
undefined NaN NaN NaN NaN 0 0 true
true NaN NaN 1 1 1 1 false
false NaN NaN 0 0 0 0 false
Infinity NaN Infinity Infinity Infinity 0 0 false
NaN NaN NaN NaN NaN 0 0 true
{} NaN NaN NaN NaN 0 0 true
{valueOf: function(){return 42}} NaN NaN 42 42 42 42 false
{toString: function(){return "56"}} 56 56 56 56 56 56 false
And the JavaScript to generate it! 
EXPRS = [
    'parseInt(x)',
    'parseFloat(x)',
    'Number(x)',
    '+x',
    '~~x',
    'x>>>0',
    'isNaN(x)'

];

VALUES = [
    '"123"',
    '"+123"',
    '"-123"',
    '"123.45"',
    '"-123.45"',
    '"12e5"',
    '"12e-5"',

    '"0123"',
    '"0000123"',
    '"0b111"',
    '"0o10"',
    '"0xBABE"',

    '"4294967295"',
    '"123456789012345678"',
    '"12e999"',

    '""',
    '"123foo"',
    '"123.45foo"',
    '"  123   "',
    '"foo"',
    '"12e"',
    '"0b567"',
    '"0o999"',
    '"0xFUZZ"',

    '"+0"',
    '"-0"',
    '"Infinity"',
    '"+Infinity"',
    '"-Infinity"',
    'BigInt(1)',

    'null',
    'undefined',
    'true',
    'false',
    'Infinity',
    'NaN',

    '{}',
    '{valueOf: function(){return 42}}',
    '{toString: function(){return "56"}}',

];

//////

function wrap(tag, s) {
    if (s && s.join)
        s = s.join('');
    return '<' + tag + '>' + String(s) + '</' + tag + '>';
}

function table(head, rows) {
    return wrap('table', [
        wrap('thead', tr(head)),
        wrap('tbody', rows.map(tr))
    ]);
}

function tr(row) {
    return wrap('tr', row.map(function (s) {
        return wrap('td', s)
    }));
}

function val(n) {
    return n === true || Number.isNaN(n) || n === "Error" ? wrap('b', n) : String(n);
}

var rows = VALUES.map(function (v) {
    var x = eval('(' + v + ')');
    return [v].concat(EXPRS.map(function (e) {
        try {
            return val(eval(e));
        } catch {
            return val("Error");
        }
    }));
});

document.body.innerHTML = table(["x"].concat(EXPRS), rows);

Tags: #javascript