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Asked: 2026-06-14T06:05:10+00:00

Simple, really. Is 0xf12345678>>>4 always supposed to produce 0x1234567 as a result in JavaScript?

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Simple, really. Is 0xf12345678>>>4 always supposed to produce 0x1234567 as a result in JavaScript? Can I assume this would work in all browsers?

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  1. Editorial Team

    Yes, according to the ECMAScript 5 specification, the >>> operator performs the internal ToUInt32 algorithm.

    See Section 11.7.3 of the spec:

    1. Let lref be the result of evaluating ShiftExpression.
    2. Let lval be GetValue(lref).
    3. Let rref be the result of evaluating AdditiveExpression.
    4. Let rval be GetValue(rref).
    5. Let lnum be ToUint32(lval).
    6. Let rnum be ToUint32(rval).
    7. Let shiftCount be the result of masking out all but the least significant 5 bits of rnum, that is, compute rnum & 0x1F.
    8. Return the result of performing a zero-filling right shift of lnum by shiftCount bits. Vacated bits are filled with zero. The result is
      an unsigned 32-bit integer.

    It is spelled out very clearly that the result is a 32-bit integer, always.

    The >>> operator is used commonly to convert to a 32-bit unsigned integer. For instance, MDN uses it in their shims. Example: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/forEach#Compatibility

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