Let it be...
Definition :
The let statement declares a block scope local variable, optionally initializing it to a value.
What different between var and let ?
It is mathematical statement.Remember in Math class, our teacher always mention let , for example:
If we let A be the statement "You are rich" and B be the statement "You are happy", then the negation of "A or B" becomes "Not A and Not B."The question already answered in : Why was the name 'let' chosen for block-scoped variable declarations in JavaScript?
The different , notice the code below is using var, once you define same variable in local scope in second time , it will overwrite the variable in global scope,
function varTest() { var x = 1; if (true) { var x = 2; // same variable! console.log(x); // 2 } console.log(x); // 2 }
Using let, help to identify which belong to which.
function letTest() { let x = 1; if (true) { let x = 2; // different variable console.log(x); // 2 } console.log(x); // 1 }
Comments
Post a Comment