Get Programming with JavaScript

Get Programming with JavaScript - Listing 7.06

Listing 7.06 - Using Math.min and Math.max to constrain an argument

var line = function (lineLength) {
    var line = "========================================";
    lineLength = Math.max(0, lineLength);
    lineLength = Math.min(40, lineLength);
    return line.substr(0, lineLength);
};

console.log(line(30));
console.log(line(40));
console.log(line(50));

Further Adventures

Listing 7.06 - Using Math.min and Math.max to constrain an argument - Task 1

Test line lengths from -20 to 60 in steps of 10.

var line = function (lineLength) {
    var line = "========================================";
    lineLength = Math.max(0, lineLength);
    lineLength = Math.min(40, lineLength);
    return line.substr(0, lineLength);
};

console.log(line(-20));
console.log(line(-10));
console.log(line(0));
console.log(line(10));
console.log(line(20));
console.log(line(30));
console.log(line(40));
console.log(line(50));
console.log(line(60));

Listing 7.06 - Using Math.min and Math.max to constrain an argument - Task 2

Define a spaces function that returns a string made up of a specified number of space characters. The line of spaces returned can have a length between 0 and 40.

var spaces = function (lineLength) {

    // create a string made up of 40 spaces
    var line = "                                        ";

    // ensure lineLength is between 0 and 40 inclusive
    lineLength = Math.max(0, lineLength);
    lineLength = Math.min(40, lineLength);

    // return a substring of the specified length
    return line.substr(0, lineLength);
};

Listing 7.06 - Using Math.min and Math.max to constrain an argument - Task 3

Add an emptyBox function that draws an empty box of specified width and height 5.

var line = function (lineLength) {
    var line = "========================================";
    lineLength = Math.max(0, lineLength);
    lineLength = Math.min(40, lineLength);
    return line.substr(0, lineLength);
};

var spaces = function (lineLength) {
    var line = "                                        ";
    lineLength = Math.max(0, lineLength);
    lineLength = Math.min(40, lineLength);
    return line.substr(0, lineLength);
};

var emptyBox = function (width) {

    // top border
    var box = "\n" + line(width);

    // middle section of height 3
    box += "\n=" + spaces(width - 2) + "=";
    box += "\n=" + spaces(width - 2) + "=";
    box += "\n=" + spaces(width - 2) + "=";

    // bottom border
    box += "\n" + line(width);

    box += "\n";

    console.log(box);
};

// test the emptyBox function
emptyBox(12);