javascript - How to test a function with different inputs -

function addtwo (a, b) {   return + b; }  //leave function call addtwo(50, 100); 

i'm learning react , i'm trying create codecademy type site 'learning project', have run js problem.

say have function above, how test more 1 case? far i'm testing with:

eval(code pulled in here) === 150 ? alert('correct!') : alert('wrong!');  

which going alert correct, ok case. other questions (and one) i'm going want more 1 test case , that's i'm stuck.

so, how can test multiple test cases, or there whole other way of doing i'm trying achieve?

any help/tips appreciated,

for know react here's code see bit of have :

const codeeditor = react.createclass({   getinitialstate () {     var initialvalue = [       "function addtwo () {",       "  ",       "}",       "//leave function call",       "addtwo(50, 100);"   ].join("\n");      return {       katavalue: initialvalue     }   },   onchange (newvalue) {     this.setstate({katavalue: newvalue});   },   evalcode () {     var val = this.state.katavalue     eval(val) === 150 ? alert('correct!') : alert('wrong!');   },   render () {     return (       <div classname="code-editor-wrapper">         <aceeditor           name="editor"           mode="sh"           theme="chaos"           onchange={this.onchange}           value={this.state.katavalue}           editorprops={{$blockscrolling: true}}         />       <button onclick={this.evalcode} classname="spec-btn submit-code-btn">evaluate</button>       </div>     )   } }) 

don't include function call in user's code. require function named in way. instead of directly evaling user's code, embed function returns user's function:

function getuserfunction(code, functionname) {   var usercode = new function(code + '; return ' + functionname + ';');   return usercode(); } 

after calling getuserfunction have reference function user wrote , can execute want. how structure test cases , how feedback want give user you.

here small example:

var userfn = getuserfunction(this.state.katavalue, 'addtwo'); var testcases = [   [[50, 100], 150],   [[1, 2], 3], ]; var passes = testcases.every(   ([input, output]) => userfn(...input) === output ); if (passes) {   // test cases pass }