减法赋值 (-=)

¥Syntax

x -= y

¥Description

x -= y 与 x = x - y 等效，只是表达式 x 仅计算一次。

¥x -= y is equivalent to x = x - y, except that the expression x is only evaluated once.

¥Examples

¥Subtraction assignment using numbers

let bar = 5;

bar -= 2; // 3

其他非 BigInt 值被强制转换为数字：

¥Other non-BigInt values are coerced to numbers:

bar -= "foo"; // NaN

¥Subtraction assignment using BigInts

let foo = 3n;
foo -= 2n; // 1n
foo -= 1; // TypeError: Cannot mix BigInt and other types, use explicit conversions

¥See also

• JS 指南中的赋值运算符
• 减法（-）