no-plusplus

禁止一元运算符 ++ 和 --

因为一元 ++ 和 -- 运算符会自动插入分号，所以空格的差异会改变源代码的语义。

var i = 10;
var j = 20;

i ++
j
// i = 11, j = 20

var i = 10;
var j = 20;

i
++
j
// i = 10, j = 21

规则详情

此规则不允许一元运算符 ++ 和 --。

此规则的错误代码示例：

/*eslint no-plusplus: "error"*/

var foo = 0;
foo++;

var bar = 42;
bar--;

for (i = 0; i < l; i++) {
    return;
}

此规则的正确代码示例：

/*eslint no-plusplus: "error"*/

var foo = 0;
foo += 1;

var bar = 42;
bar -= 1;

for (i = 0; i < l; i += 1) {
    return;
}

选项

VtL0QjEmIoPGGZlPIOT+lHJvS1I3iz4tkRMrlBEMYEjqkAmYbAoIMmWhq1OHxJs7

ZoK5QQYs4d64QXQdqnl7IIJo+nIbdDRQfHkoLRitdqcxNp7R6EtO8UeVzR7ibymCYN8pHuFOUjMfxzsccrR1SLSV4OyJMCgiQohrPGBJ7iauF7iEfzgLgvfLeXoNgyVpRUAL5uV6iS5WfznybC/44HIDtU9iPWNcn5PeyxD6kWLe5FGy3v46avrL+FAuYzxPEYrdFrovL6/TJHJLYJqNCQr+5M+khWAIZjnOMucqosdS3/F0PKeTsmHNVnrTL9SV

allowForLoopAfterthoughts

TlLpo7HIJjIy2v3f96HaCWHv9ZNzOkELx917A7qaUY9uiom7iLhWxeYjFu0EcYpiGTxf2gRoNqk76zN51r0ESAOzK0b3u+MqCRaTDJ3QHvNGlzVc9tpuES9hr9FQUruVSqC+tVHZlRW3C4ZFl5wQVA==

/*eslint no-plusplus: ["error", { "allowForLoopAfterthoughts": true }]*/

for (i = 0; i < l; i++) {
    doSomething(i);
}

for (i = l; i >= 0; i--) {
    doSomething(i);
}

for (i = 0, j = l; i < l; i++, j--) {
    doSomething(i, j);
}

TlLpo7HIJjIy2v3f96HaCWHv9ZNzOkELx917A7qaUY9uiom7iLhWxeYjFu0EcYpiGTxf2gRoNqk76zN51r0ESNkKnGnAn6f6Qti1XaMOdqBjwI81jkGv0XGmWcPcQPNvzoftxdh5DZDDibV4jU1tEw==

/*eslint no-plusplus: ["error", { "allowForLoopAfterthoughts": true }]*/

for (i = 0; i < l; j = i++) {
    doSomething(i, j);
}

for (i = l; i--;) {
    doSomething(i);
}

for (i = 0; i < l;) i++;