Hungry big front node. JS Advanced Tutorial-javascript Basic problem-scope

"Hungry big front node. JS Advanced Tutorial" Address: Https://github.com/ElemeFE/node-interview

Scope in a sense, it is a difficult point, it needs you really understand JS participle, lexical analysis, grammar analysis, code generation, LHS query, RHS Query and other deep things.

If you don't know, you can read "JavaScript you don't know: roll up."

The difference between let and Var

1.let is only valid in a declared code block, and the Let declaration variable is used in {}, which is not accessible outside, which is the block-level scope

2. There are no variable promotion issues

3. Repeated statements will error

Hungry big front node. JS Advanced Tutorial-javascript Basic problem-scope