减法赋值 (-=)

减法赋值 (-=) 运算符对两个操作数执行 subtraction 并将结果赋给左侧操作数。

¥The subtraction assignment (-=) operator performs subtraction on the two operands and assigns the result to the left operand.

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¥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

¥Using subtraction assignment

let bar = 5;

bar -= 2; // 3
bar -= "foo"; // NaN

let foo = 3n;
foo -= 2n; // 1n

Specification
ECMAScript Language Specification # sec-assignment-operators

¥Specifications

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¥See also