What is the difference between Number(…) and parseFloat(…)

Question

What is the difference between parseInt(string) and Number(string) in JavaScript has been asked previously.

But the answers basically focused on the radix

Answer 1

Please excuse me posting yet another answer, but I just got here via a Google search and did not find all of the details that I wanted. Running the following code in Node.js:

var vals = ["1", "1.1", "0", "1.1abc", "", " ", null];
for(var i = 0; i < vals.length; i++){
  var ifTest = false;
  if(vals[i])
  {
    ifTest = true;
  }
  console.log("val=" + vals[i] + ", Number()=" + Number(vals[i])+ ", parseFloat()=" + parseFloat(vals[i]) + ", if()=" + ifTest);
}

gives the following output:

val=1, Number()=1, parseFloat()=1, if()=true
val=1.1, Number()=1.1, parseFloat()=1.1, if()=true
val=0, Number()=0, parseFloat()=0, if()=true
val=1.1abc, Number()=NaN, parseFloat()=1.1, if()=true
val=, Number()=0, parseFloat()=NaN, if()=false
val= , Number()=0, parseFloat()=NaN, if()=true
val=null, Number()=0, parseFloat()=NaN, if()=false

Some noteworthy takeaways:

1. If protecting with an if(val) before trying to convert to number, then parseFloat() will return a number except in the whitespace case.
2. Number returns a number in all cases except for non-numeric characters aside from white-space.

Please feel free to add any test cases that I may be missing.