Today #Day127 of #365DaysOfCode, Learning Essential JavaScript Interview Questions.
21. What will the following code output to the console and why
var hero = {
_name: 'John Doe',
getSecretIdentity: function (){
return this._name;
}
};
var stoleSecretIdentity = hero.getSecretIdentity;
console.log(stoleSecretIdentity());
console.log(hero.getSecretIdentity());
What is the issue with this code and how can it be fixed.
M-1
var hero = {
_name: 'John Doe',
getSecretIdentity: function (){
return this._name;
}
};
var stoleSecretIdentity = hero.getSecretIdentity;
console.log(stoleSecretIdentity());
console.log(hero.getSecretIdentity());
const stoleSecretIdentity2 = hero.getSecretIdentity.bind(hero)
console.log(stoleSecretIdentity2());
M-2
var hero = {
_name: 'John Doe',
getSecretIdentity: function (){
return this._name;
}
};
var stoleSecretIdentity = hero.getSecretIdentity;
console.log(stoleSecretIdentity());
console.log(hero.getSecretIdentity());
var stoleSecretIdentity3 = hero.getSecretIdentity();
console.log(stoleSecretIdentity3);
22. Create a function that,
given a DOM Element on the page, will visit the element itself and all of its descendants (not just its immediate children).
For each element visited, the function should pass that element to a provided callback function.
The arguments to the function should be:
a DOM element
a callback function (that takes a DOM element as its argument)
Visiting all elements in a tree (DOM) is a classic Depth-First-Search algorithm application.
Here’s an example solution:
function Traverse(p_element,p_callback) {
p_callback(p_element);
var list = p_element.children;
for (var i = 0; i < list.length; i++)
{
Traverse(list[i],p_callback); // recursive call
}
}
Conclusion
Learned and practiced Essential JavaScript Interview Questions involving topics like Object method and function recursion.
Code
code
