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(<<)

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(<<) (32 ) . . 0 .

In this article

const a = 5; // 00000000000000000000000000000101
const b = 2; // 00000000000000000000000000000010

console.log(a << b); // 00000000000000000000000000010100
// Expected output: 20

js
a << b

. . 0 .

, 9 << 2 36 .

     9 (10): 00000000000000000000000000001001 (2)
                  --------------------------------
9 << 2 (10): 00000000000000000000000000100100 (2) = 36 (10)

x y x * 2 ** y. 9 << 3 9 * (2 ** 3) = 9 * (8) = 72 .

32 . , 32 /.

32 32 0 31 . , 100 << 32 100 << 0 ( 100). 32 0 .

js
9 << 3; // 72
// 9 * (2 ** 3) = 9 * (8) = 72

Specification
ECMAScript 2027 LanguageSpecification
# sec-left-shift-operator

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  1. JavaScript
  2. :
  3. JavaScript
    7. Numbers and strings
    8. Representing dates & times
    10. index
    11. key
    13. class
    14. promise
    15. JavaScript
    17. Resource management
    18. Internationalization
    19. JavaScript
    1. JavaScript (JS )
    2. JavaScript
    3. JavaScript
  6. :
    1. AbstractModuleSource
    2. AggregateError
    3. Array
    4. ArrayBuffer
    5. AsyncDisposableStack
    6. AsyncFunction
    7. AsyncGenerator
    8. AsyncGeneratorFunction
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    11. BigInt
    12. BigInt64Array
    13. BigUint64Array
    14. Boolean
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    17. decodeURI()
    18. decodeURIComponent()
    19. DisposableStack
    20. encodeURI()
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    22. Error
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    25. EvalError
    26. FinalizationRegistry
    27. Float16Array
    28. Float32Array
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    30. Function
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    33. globalThis
    34. Infinity
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    36. Int16Array
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    11. Bitwise OR assignment (|=)
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    14. class
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    45. (*)
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    47. new operator
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    50. Nullish coalescing assignment (??=)
    51. Nullish coalescing operator
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    56. (%)
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    58. (>>)
    59. Right shift assignment (>>=)
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  11. Classes
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    6. Class static initialization blocks
    1. Backreference: \1, \2
    2. Buffer boundary assertion: \A, \z, \Z
    3. Capturing group: (...)
    4. Character class escape: \d, \D, \w, \W, \s, \S
    5. Character class: [...], [^...]
    6. Character escape: \n, \u{...}
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    1. AggregateError: No Promise in Promise.any was resolved
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    43. SyntaxError: incomplete quantifier in regular expression
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    45. SyntaxError: invalid BigInt syntax
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    47. SyntaxError: invalid character in class in regular expression
    48. SyntaxError: invalid class set operation in regular expression
    49. SyntaxError: invalid decimal escape in regular expression
    50. SyntaxError: invalid identity escape in regular expression
    51. SyntaxError: invalid named capture reference in regular expression
    52. SyntaxError: invalid property name in regular expression
    53. SyntaxError: invalid range in character class
    54. SyntaxError: invalid regexp group
    55. SyntaxError: invalid regular expression flag "x"
    56. SyntaxError: invalid unicode escape in regular expression
    57. SyntaxError: JSON.parse: bad parsing
    58. SyntaxError: label not found
    59. SyntaxError: missing : after property id
    60. SyntaxError: missing ) after argument list
    61. SyntaxError: missing ) after condition
    62. SyntaxError: missing ] after element list
    63. SyntaxError: missing } after function body
    64. SyntaxError: missing } after property list
    65. SyntaxError: missing = in const declaration
    66. SyntaxError: Malformed formal parameter
    67. SyntaxError: missing name after . operator
    68. SyntaxError: missing variable name
    69. SyntaxError: negated character class with strings in regular expression
    70. SyntaxError: new keyword cannot be used with an optional chain
    71. SyntaxError: nothing to repeat
    72. SyntaxError: numbers out of order in {} quantifier.
    73. SyntaxError: octal escape sequences can't be used in untagged template literals or in strict mode code
    74. SyntaxError: parameter after rest parameter
    75. SyntaxError: private fields can't be deleted
    76. SyntaxError: property name __proto__ appears more than once in object literal
    77. SyntaxError: raw bracket is not allowed in regular expression with unicode flag
    78. SyntaxError: redeclaration of formal parameter "x"
    79. SyntaxError: reference to undeclared private field or method #x
    80. SyntaxError: rest parameter may not have a default
    81. SyntaxError: return not in function
    82. SyntaxError: setter functions must have one argument
    83. SyntaxError: string literal contains an unescaped line break
    84. SyntaxError: super() is only valid in derived class constructors
    85. SyntaxError: tagged template cannot be used with optional chain
    86. SyntaxError: Unexpected '#' used outside of class body
    87. SyntaxError: Unexpected token
    88. SyntaxError: unlabeled break must be inside loop or switch
    89. SyntaxError: unparenthesized unary expression can't appear on the left-hand side of '**'
    90. SyntaxError: use of super property/member accesses only valid within methods or eval code within methods
    91. SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead
    92. ReferenceError: deprecated caller or arguments usage
    93. TypeError: 'x' is not iterable
    94. TypeError: "x" is (not) "y"
    95. TypeError: "x" is not a constructor
    96. TypeError: "x" is not a function
    97. TypeError: "x" is not a non-null object
    98. TypeError: "x" is read-only
    99. TypeError: already executing generator
    100. TypeError: BigInt value can't be serialized in JSON
    101. TypeError: calling a builtin X constructor without new is forbidden
    102. TypeError: can't access/set private field or method: object is not the right class
    103. TypeError: can't assign to property "x" on "y": not an object
    104. TypeError: can't convert BigInt to number
    105. TypeError: can't convert x to BigInt
    106. TypeError: can't define property "x": "obj" is not extensible
    107. TypeError: can't delete non-configurable array element
    108. TypeError: can't redefine non-configurable property "x"
    109. TypeError: can't set prototype of this object
    110. TypeError: can't set prototype: it would cause a prototype chain cycle
    111. TypeError: cannot use 'in' operator to search for 'x' in 'y'
    112. TypeError: class constructors must be invoked with 'new'
    113. TypeError: cyclic object value
    114. TypeError: derived class constructor returned invalid value x
    115. TypeError: getting private setter-only property
    116. TypeError: Initializing an object twice is an error with private fields/methods
    117. TypeError: invalid 'instanceof' operand 'x'
    118. TypeError: invalid Array.prototype.sort argument
    119. TypeError: invalid assignment to const "x"
    120. TypeError: Iterator/AsyncIterator constructor can't be used directly
    121. TypeError: matchAll/replaceAll must be called with a global RegExp
    122. TypeError: More arguments needed
    123. TypeError: "x" has no properties
    124. TypeError: property "x" is non-configurable and can't be deleted
    125. TypeError: Reduce of empty array with no initial value
    126. TypeError: setting getter-only property "x"
    127. TypeError: WeakSet key/WeakMap value 'x' must be an object or an unregistered symbol
    128. TypeError: X.prototype.y called on incompatible type
    129. URIError: malformed URI sequence
    130. Warning: -file- is being assigned a //# sourceMappingURL, but already has one
    131. Warning: unreachable code after return statement
    1. JavaScript
    2. Execution model
    3. Lexical
    4. Magic comments
    5. Iteration
    8. Trailing commas
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