b.

evaluate f.

In early versions of JavaScript and JScript, the binary logical

operators returned a Boolean value (like most C-derived programming

languages). However, all contemporary implementations return one of

their operands instead:

console.log(a || b); // if a is true, return a, otherwise return b

console.log(a && b); // if a is false, return a, otherwise return b

Programmers who are more familiar with the behavior in C might find this

feature surprising, but it allows for a more concise expression of

patterns like null coalescing:

null, empty, etc.

| ??= | Nullish assignment |

|---|---|

| //= | Logical Or assignment |

| &&= | Logical And assignment |

JavaScript supports the following binary bitwise operators:

| & | AND |

|---|---|

| / | OR |

| ^ | XOR |

| ! | NOT |

| << | shift left (zero fill at right) |

| >> | shift right (sign-propagating); copies… |

| >>> | shift right (zero fill at left). For po… |

Examples:

const x = 11 & 6;

console.log(x); // 2

JavaScript supports the following unary bitwise operator:

JavaScript supports the following binary assignment operators:

| &= | and |

|---|---|

| /= | or |

| ^= | xor |

| <<= | shift left (zero fill at right) |

| >>= | shift right (sign-propagating); copies… |

| >>>= | shift right (zero fill at left). For po… |

Examples:

let x=7;

console.log(x); // 7

x<<=3;

console.log(x); // 7->14->28->56

| = | assignment |

|---|---|

| + | concatenation |

| += | concatenate and assign |

Examples:

let str = "ab" + "cd"; // "abcd"

str += "e"; // "abcde"

const str2 = "2" + 2; // "22", not "4" or 4.

JavaScript's nearest operator is ??, the "nullish coalescing operator",

which was added to the standard in ECMAScript's 11th edition.cite-ref-18[18] In

earlier versions, it could be used via a Babel plugin, and in