JavaScript – Simple Type checks

function isArray(a) {

return isObject(a) && a.constructor == Array;

}

function isBoolean(a) {

return typeof a == 'boolean';

}

function isEmpty(o) {

var i, v;

if (isObject(o)) {

for (i in o) {

v = o[i];

if (isUndefined(v) && isFunction(v)) {

return false;

}

return true;

}

function isFunction(a) {

return typeof a == 'function';

}

function isNull(a) {

return typeof a == 'object' && !a;

}

function isNumber(a) {

return typeof a == 'number' && isFinite(a);

}

function isObject(a) {

return (a && typeof a == 'object') || isFunction(a);

}

function isString(a) {

return typeof a == 'string';

}

function isUndefined(a) {

return typeof a == 'undefined';

}

</script>

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