inherit is not Defined

Question

I'm studying a javascript book, and i have this example

 var p = {
// x and y are regular read-write data properties. x: 1.0,
    y: 1.0,
// r is a read-write accessor property with getter and setter. // Don't forget to put a comma after accessor methods.
    get r() {
        return Math.sqrt(this.x * this.x + this.y * this.y);
    }, set r(newvalue) {
        var oldvalue = Math.sqrt(this.x * this.x + this.y * this.y);
        var ratio = newvalue / oldvalue;
        this.x *= ratio;
        this.y *= ratio;
    },
    // theta is a read-only accessor property with getter only.
    get theta() {
        return Math.atan2(this.y, this.x);
    } };

var q = inherit(p); // Create a new object that inherits getters and setters
q.x = 0; q.y = 0; // Create q's own data properties
console.log(q.r); // And use the inherited accessor properties console.log(q.theta);

But I have this error Uncaught ReferenceError: inherit is not defined

Answer 1

Looking up this code on internet suggests you might be reading O'Reilly's 'JavaScript: the Definitive Guide'. If so, the code for inherit() is given in example 6-1: See here: https://www.inkling.com/read/javascript-definitive-guide-david-flanagan-6th/chapter-6/creating-a-new-object-that

Answer 2

To add to Mchl's answer (I had the same problem, but couldn't follow the link in his answer), the following is the code for the inherit function as in Javascript The Definitive Guide's example 6.1:

// inherit() returns a newly created object that inherits properties from the
// prototype object p.  It uses the ECMAScript 5 function Object.create() if
// it is defined, and otherwise falls back to an older technique.
function inherit(p) {
    if (p == null) throw TypeError(); // p must be a non-null object
    if (Object.create)                // If Object.create() is defined...
        return Object.create(p);      //    then just use it.
    var t = typeof p;                 // Otherwise do some more type checking
    if (t !== "object" && t !== "function") throw TypeError();
    function f() {};                  // Define a dummy constructor function.
    f.prototype = p;                  // Set its prototype property to p.
    return new f();                   // Use f() to create an "heir" of p.