block-scoped-var
Enforce the use of variables within the scope they are defined
当变量在其定义的块之外被使用时，block-scoped-var 规则会产生警告。这模拟了 C 语言的块范围。
规则细节
这条规则的目的是减少变量在其绑定上下文之外的使用，并模仿其他语言的传统块范围。这是为了帮助语言的新手们避免因变量提升而产生的地狱。
此规则的错误示例：
Open in Playground
/*eslint block-scoped-var: "error"*/
function doIf() {
if (true) {
var build = true;
}
console.log(build);
}
function doIfElse() {
if (true) {
var build = true;
} else {
var build = false;
}
}
function doTryCatch() {
try {
var build = 1;
} catch (e) {
var f = build;
}
}
function doFor() {
for (var x = 1; x < 10; x++) {
var y = f(x);
}
console.log(y);
}
class C {
static {
if (something) {
var build = true;
}
build = false;
}
}
此规则的正确示例：
Open in Playground
/*eslint block-scoped-var: "error"*/
function doIf() {
var build;
if (true) {
build = true;
}
console.log(build);
}
function doIfElse() {
var build;
if (true) {
build = true;
} else {
build = false;
}
}
function doTryCatch() {
var build;
var f;
try {
build = 1;
} catch (e) {
f = build;
}
}
function doFor() {
for (var x = 1; x < 10; x++) {
var y = f(x);
console.log(y);
}
}
class C {
static {
var build = false;
if (something) {
build = true;
}
}
}
Version
This rule was introduced in ESLint v0.1.0.
Further Reading
