eval code example

Example 1: Calculate string value in javascript, not using eval

let str = "12/5*9+9.4*2"

let res1 = eval(str)
console.log('res1:', res1)

let res2 = (new Function('return '+str)())
console.log('res2:', res2)

Example 2: javascript execute string code

var theInstructions = "alert('Hello World'); var x = 100";

var F=new Function (theInstructions);

return(F());

Example 3: what is the meaning of eval

// Eval is a function which evaluates a string as though it were an expression and returns a result.

Example 4: eval

Just use eval command for running string output. As for example:
eval $cmd   #execute command included in string value of $cmd variable
Or for a more sophisticated use run commands stored in lines of a file:
cat commands_file.txt | while read line; do eval $line; done

Example 5: convert string of expression in to expression in javascript

eval(string)