1 console.log("Undefined --------------------------------------------------------------");
2 let u = undefined;
3 console.log("u", u);
4
5 console.log("Number -----------------------------------------------------------------");
6 let i = 1;
7 let f = 1.0;
8 let l = 10_000;
9 let binary = 0b1010;
10 console.log("0b1010", binary);
11 let octal = 0o12;
12 console.log("0o12", octal );
13 let hex = 0xA;
14 console.log("0xA", hex);
15 console.log(
16 Number.MIN_VALUE,
17 Number.MIN_SAFE_INTEGER,
18 Number.MAX_SAFE_INTEGER,
19 Number.MAX_VALUE,
20 );
21 let x = NaN;
22 let y = Infinity;
23 let z = -Infinity;
24
25
26
27 console.log("i =", i, "; i++ ", i++);
28 console.log("i =", i, "; ++i ", ++i);
29 console.log("2 ** 4 === 0 ", 2 ** 4);
30 console.log("7 % 3 === ", 7 % 3);
31 console.log("1 / 0 === ", 1 / 0);
32
33
34 console.log("BigInt -----------------------------------------------------------------");
35 let ib = 1n;
36 console.log(100n === BigInt(100));
37 console.log(Number.MAX_SAFE_INTEGER + 2102);
38 console.log(BigInt(Number.MAX_SAFE_INTEGER) + 2102n);
39
40
41 console.log("Boolean ----------------------------------------------------------------");
42 let b = true;
43 console.log("Boolean(undefined)", Boolean(undefined));
44 console.log(null == true ? "true" : "false");
45
46
47 console.log("(Quasi-)Logische Operatoren -------------------------------------------");
48 console.log('1 && "1": ', 1 && "1");
49 console.log('null && "1": ', null && "1");
50 console.log("null && true: ", null && true);
51 console.log("true && null: ", true && null);
52 console.log("null && false: ", null && false);
53 console.log("{} && true: ", {} && true);
54
55
56
57
58
59 console.log('1 ?? "1": ', 1 ?? "1");
60 console.log('null ?? "1": ', null ?? "1");
61 console.log("null ?? true: ", null ?? true);
62 console.log("true ?? null: ", true ?? null);
63 console.log("null ?? false: ", null ?? false);
64 console.log("{} ?? true: ", {} ?? true);
65
66 console.log('undefined ?? "1": ', undefined ?? "1");
67 console.log('undefined ?? "1": ', undefined ?? "1");
68 console.log("undefined ?? true: ", undefined ?? true);
69 console.log("true ?? undefined: ", true ?? undefined);
70 console.log("undefined ?? false: ", undefined ?? false);
71 console.log("undefined ?? undefined: ", undefined ?? undefined);
72
73
74 console.log("Strings ----------------------------------------------------------------");
75 let _s = "42";
76 console.log("Die Antwort ist " + _s + ".");
77 console.log(`Die Antwort ist ${_s}.`);
78
79 console.log(`
80 Die Antwort mag ${_s} sein,
81 aber was ist die Frage?`);
82
83 console.log(String(42));
84
85
86 console.log("Objekte ----------------------------------------------------------------");
87 let emptyObject = null;
88 let anonymousObj = {
89 i: 1,
90 u: { j: 2, v: { k: 3 } },
91 toString: function () {
92 return "anonymousObj";
93 },
94 "?" : "question mark"
95 };
96
97 anonymousObj.j = 2;
98 anonymousObj["j"] = 4;
99 anonymousObj["k"] = 3;
100 console.log("anonymousObj: ", anonymousObj);
101 console.log("anonymousObj.toString(): ", anonymousObj.toString());
102 delete anonymousObj["?"];
103 delete anonymousObj.toString;
104 console.log("anonymousObj.toString() [original]", anonymousObj.toString());
105
106
107
108
109 console.log("anonymousObj.u?.v.k", anonymousObj.u?.v.k);
110 console.log("anonymousObj.u.v?.k", anonymousObj.u.v?.k);
111 console.log("anonymousObj.u.v?.z", anonymousObj.u.v?.z);
112 console.log("anonymousObj.u.q?.k", anonymousObj.u.q?.k);
113 console.log("anonymousObj.p?.v.k", anonymousObj.p?.v.k);
114
115
116 anonymousObj.name ||= "Max Mustermann";
117
118
119
120 console.log("Date -------------------------------------------------------------------");
121 let date = new Date("8.6.2024");
122 console.log(date);
123
124
125 console.log("Funktionen sind auch Objekte -------------------------------------------");
126 let func = function () {
127 return "Hello World";
128 };
129 console.log(func, func());
130
131
132 console.log("Arrays -----------------------------------------------------------------");
133 let temp = undefined;
134 let $a = [1];
135 console.log("let $a = [1]; $a, $a.length", $a, $a.length);
136 $a.push(2);
137 console.log("$a.push(2); $a", $a);
138 temp = $a.unshift(0);
139 console.log("temp = $a.unshift(0); temp, $a", temp, $a);
140 temp = $a.shift();
141 console.log("temp = $a.shift(); temp, $a", temp, $a);
142
143 console.log("Array.isArray($a)", Array.isArray($a));
144 console.log("Array.isArray({})", Array.isArray({}));
145 console.log("Array.isArray(1)", Array.isArray(1));
146
147
148 console.log("Symbols ---------------------------------------------------------------");
149 let sym1 = Symbol("1");
150 let sym2 = Symbol("1");
151 let obj1Values = { sym1: "value1", sym2: "value2" };
152 console.log(obj1Values);
153 console.log(`sym1 in ${JSON.stringify(obj1Values)}: `, sym1 in obj1Values);
154 let obj2Values = { [sym1]: "value1", [sym2]: "value2" };
155 console.log(obj2Values);
156 console.log(`sym1 in ${JSON.stringify(obj2Values)}: `, sym1 in obj2Values);
157 console.log(obj1Values, " vs. ", obj2Values);
158
159 console.log( { sym1 : "this", sym1 : "that" });
160 console.log("sym1 == sym2", sym1 == sym2);
