js__coffeescript__codeschool/lib/3-2-operators.js

91 lines
1.7 KiB
JavaScript

/*
Operators
---------
CoffeScript JavaScript
== is ===
!= isnt !==
not !
and &&
or ||
true yes on true
false no off false
*/
var Decaf, addCaffeine, base, base1, base2, coffee, cupsOfCoffee, level, message, paid, pour;
paid = coffee = pour = function() {};
if (paid() && coffee() === true) {
pour();
}
addCaffeine = Decaf = function() {};
if (!Decaf()) {
addCaffeine();
}
if (!Decaf()) {
addCaffeine();
}
// Combined range checks
level = 4;
if ((2 < level && level < 5)) {
alert("In range");
}
// Functional switch.
message = (function() {
switch (cupsOfCoffee) {
case 0:
return 'Asleep';
case 1:
return 'Eyes open';
case 2:
return 'Buzzed';
default:
return 'Dangerous';
}
})();
// Existential check: not undefined and not null.
if (typeof cupsOfCoffee !== "undefined" && cupsOfCoffee !== null) {
alert('Exists');
}
if (typeof cupsOfCoffee !== "undefined" && cupsOfCoffee !== null) {
alert('Exists');
}
// Not strictly identical to the two shorter forms below.
if (typeof cupsOfCoffee === "undefined" || cupsOfCoffee === null) {
cupsOfCoffee = 0;
}
if (cupsOfCoffee == null) {
cupsOfCoffee = 0;
}
if (cupsOfCoffee == null) {
cupsOfCoffee = 0;
}
if (typeof coffeePot !== "undefined" && coffeePot !== null) {
coffeePot.brew();
}
if (typeof vehicle.start_engine === "function") {
if (typeof (base = vehicle.start_engine()).shift_gear === "function") {
if (typeof (base1 = base.shift_gear()).crank === "function") {
if (typeof (base2 = base1.crank()).press_gas === "function") {
base2.press_gas();
}
}
}
}
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