Infinity

⟩ ⟩ ⟩ ⟩ ⟩ Infinity
⟩ ⟩ ⟩ ⟩ ⟩ Infinity

a property of the global object. (that is, a variable in global scope).
initial value of Infinity is .
Infinity is greater than any other .

synonyms： "positive infinity"

Infinity

yields ±Infinity (no error)
converts to 0 when used as operands of bitwise operator.

replit -

const M = Number.MAX_VALUE;     // = 1.7976931348623157e+308 ≈ 2¹⁰²⁴
const D = Math.pow(2, 970);     // 2⁹⁷⁰
const d = Math.pow(2, 969);     // 2⁹⁶⁹

// -------- Infinity --------

 1 / 0,     //  Infinity
-1 / 0,     // -Infinity

 Infinity === Number.POSITIVE_INFINITY, // true
-Infinity === Number.NEGATIVE_INFINITY, // true

3 + Infinity,           // Infinity
3 / Infinity,           //  0
-3 / Infinity,          // -0
Infinity / Infinity,    // NaN

// -------- Number.MAX_VALUE --------

M,                      // 1.7976931348623157e+308

// ⭐️ 只要 M 的最後一位 (2⁹⁷¹) 的一半 = 2⁹⁷⁰ 就足以讓 M 「進位」變成 Infinity
M + D,                  // Infinity

// ⭐️ 再小的話，則會被直接「捨棄」。
M + d,                  // M

// -------- Number.MAX_SAFE_INTEGER --------

Number.MAX_SAFE_INTEGER,    // 9007199254740991 = 2⁵³ - 1
Math.pow(2, 53) - 1,        // 9007199254740991

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Last updated 2 years ago

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