Is if possible to use variable in if statement that is not true or false-CodePudding

Wondering if this is possible and if so , how ?

var variable = true;
if (variable) {
    var newVariable = "$('table').find('tr').length > 1)";
} else {
    var newVariable = "$('table').find('tr').length > 4)";
}
if (newVariable){ // if $('table').find('tr').length > 1)
    console.log(newVariable)
}

I would like the if to look like this by inserting using the newVariable when variable is true

if ($('table').find('tr').length > 1)){
    console.log(newVariable)
}

of if variable is false then this

if ($('table').find('tr').length > 4)){
    console.log(newVariable)
}

CodePudding user response：

newVariable is a string. Using it in an if condition is not going to execute it, it will just test if the string is empty or not.

You can use a function instead, and call it in the if.

var variable = true;
if (variable) {
    var newVariable = () => $('table').find('tr').length > 1;
} else {
    var newVariable = () => $('table').find('tr').length > 4;
}
if (newVariable()){
    console.log(newVariable)
}

CodePudding user response：

Unclear why you would need to use strings. Only way you could do that is use eval or new Function and that is not a good idea. Seems like the code could be cleaned up to be either

var newVariable;
if (variable) {     
  newVariable = $('table').find('tr').length > 1; 
} else {     
  newVariable = $('table').find('tr').length > 4;
}
if (newVariable) {
  console.log('here');
}

better yet reducing the code with ternary

const minNumElems = variable ? 1 : 4;
const isValid = $('table').find('tr').length > minNumElems;
if (isValid) {
  console.log('here');
}

Or better yet using ternary