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  background: black
  color: #eee


const assert = {
    isTrue: (arg1, msg = '') =>
        (arg1 === true) ?'PASSED: '+msg) : console.error('FAILED: ' + msg),
    isFalse: (arg1, msg = '') =>
        (arg1 === false) ?'PASSED: '+msg) : console.error('FAILED: ' + msg)

const data = {
    flat: 42,
    nest: {
        foo: "foo one",
        bar: {
            can: "can one"
    arr : [ "joe" ],
    arr2: [ {magic: 'mike'}],
    zero: 0,
    empty: '',
    nulltest: null,
    nantest: NaN

const propExists = (obj, path) => {
    return !!path.split(".").reduce((obj, prop) => {
        if ( obj[prop] === 0 || obj[prop] === '' || obj[prop] === null || obj[prop] === NaN ) return true;
        return obj && obj[prop] ? obj[prop] : undefined;
    }, obj)

// falsy 'edge cases'
assert.isTrue(propExists(data, "zero"),'test for 0');
assert.isTrue(propExists(data, "empty"),'test for empty string');
assert.isTrue(propExists(data, "nulltest"),'test for null');

assert.isTrue(propExists(data, "flat"),'simple test');
assert.isTrue(propExists(data, ""),'2nd degree');
assert.isTrue(propExists(data, ""),'obj');
assert.isTrue(propExists(data, ""),'3rd degree');
assert.isTrue(propExists(data, "arr.0"),'array in obj');
assert.isTrue(propExists(data, "arr2.0.magic"), 'prop in object in array')

assert.isFalse(propExists(data, "xyz"), 'not there first sight');
assert.isFalse(propExists(data, "flat2.nosub"),'not there child');
assert.isFalse(propExists(data, ""),'partially there');
assert.isFalse(propExists(data, ""),'tip of the leave');
assert.isFalse(propExists(data, "arr.1"),'wrong array index');