Number.prototype.toExponential()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. Itโs been available across browsers since โจ2015ๅนด7ๆโฉ.
toExponential() ใฏ Number ๅคใฎใกใฝใใใงใใใฎๆฐๅคใใๆๆฐ่กจ่จใง่กจใใๆๅญๅใ่ฟใใพใใ
่ฉฆใใฆใฟใพใใใ
function expo(x, f) {
return Number.parseFloat(x).toExponential(f);
}
console.log(expo(123456, 2));
// ไบๆณใใใ็ตๆ: "1.23e+5"
console.log(expo("123456"));
// ไบๆณใใใ็ตๆ: "1.23456e+5"
console.log(expo("oink"));
// ไบๆณใใใ็ตๆ: "NaN"
ๆงๆ
toExponential()
toExponential(fractionDigits)
ๅผๆฐ
fractionDigits็็ฅๅฏ-
ใชใใทใงใณใงใใๅฐๆฐ็นใฎๅพใฎๆกๆฐใๆๅฎใใๆดๆฐใงใใ ๆขๅฎๅคใฏใใฎๆฐใ่กจใใฎใซๅฟ ่ฆใชๆฐใฎๆกใงใใ
่ฟๅค
Number ใชใใธใงใฏใใใๆๆฐ่กจ่จ (ๅฐๆฐ็นๅใฏ 1 ๆกใๅฐๆฐ็นใฎๅพใฏ fractionDigits ใซใใฃใฆๆๅฎใใใๆกใงๅใๆจใฆ) ใง่กจใใๆๅญๅใงใใ
ไพๅค
RangeError-
fractionDigitsใ0ไปฅไธ100ไปฅไธใงใฏใชใๅ ดๅใซ็บ็ใใพใใ TypeError-
ใใฎใกใฝใใใ
Numberใงใฏใชใใชใใธใงใฏใใซๅฏพใใฆๅผใณๅบใใใๅ ดๅใซ็บ็ใใพใใ
่งฃ่ชฌ
fractionDigits ๅผๆฐใ็็ฅใใใๅ ดๅใๅฐๆฐ็นใฎๅพใฎๆกๆฐใฏใใใฎๅคใ็นๅฎใใใฎใซๅฟ
่ฆใชๆกๆฐใซใชใใพใใ
toExponential ใกใฝใใใ 1 ใคใฎๆฐๅคใชใใฉใซใใพใใฏใๆๆฐใๅฐๆฐ็นใใชใๆฐๅคใชใใฉใซใซๅฏพใใฆไฝฟ็จใใๅ ดๅใใใใใๅฐๆฐ็นใจใใฆ่งฃ้ใใใใใจใ้ฒใใใใซใใกใฝใใๅผใณๅบใใซๅ
็ซใคใใใใฎๅใซ็ฉบ็ฝใ็ฝฎใใฆใใ ใใใ
ๅผๆฐ fractionDigits ใงๆๅฎใใใๆกใใใๅคใใฎๆกใๆใฃใฆใใๆฐใฎๅ ดๅใใใฎๆฐใฏใfractionDigits ใฎๆกใง่กจใใใจใใงใใๆใ่ฟใๆฐใง่กจใใใพใใtoFixed() ใกใฝใใใฎ่ชฌๆใซใใใๆฆๆฐ่กจ็พใฎ่ชฌๆใๅ็
งใใฆใใ ใใใใใใฏใtoExponential ใกใฝใใใซใ้ฉ็จใใใพใใ
ไพ
toExponential ใฎไฝฟ็จ
const numObj = 77.1234;
console.log(numObj.toExponential()); // 7.71234e+1 ใจ่กจ็คบ
console.log(numObj.toExponential(4)); // 7.7123e+1 ใจ่กจ็คบ
console.log(numObj.toExponential(2)); // 7.71e+1 ใจ่กจ็คบ
console.log((77.1234).toExponential()); // 7.71234e+1 ใจ่กจ็คบ
console.log((77).toExponential()); // 7.7e+1 ใจ่กจ็คบ
ไปๆงๆธ
| Specification |
|---|
| ECMAScriptยฎ 2026 Language Specification # sec-number.prototype.toexponential |
ใใฉใฆใถใผใฎไบๆๆง
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