lexical-closures | 易学教程

Prevent JavaScript closure from inheriting scope

阅读更多关于 Prevent JavaScript closure from inheriting scope

I am looking for a fancy way to prevent a closure from inheriting surrounding scrope. For example: let foo = function(t){ let x = 'y'; t.bar = function(){ console.log(x); // => 'y' }); }; there are only two ways I know of preventing sharing scope: (1) Use shadow variables: let foo = function(t){ let x = 'y'; t.bar = function(x){ console.log(x); // => '?' }); }; (2) Put the function body somewhere else: let foo = function(t){ let x = 'y'; t.bar = createBar(); }; My question is - does anyone know of a 3rd way to prevent closures from inheriting scope in JS? Something fancy is fine. The only

Accessing VUE JS's data from Axios

阅读更多关于 Accessing VUE JS's data from Axios

问题 I have a Vue JS (Vuetify) App that makes an ajax request that I would like to populate a div's content with the response, however I am having difficulties accessing the instance's data . All examples I have seen use this to point to the data object, but when I do I get this error Unable to set property 'message' of undefined or null reference The app is quite simple: main.js : import Vue from 'vue' import App from './App.vue' import Vuetify from 'vuetify' Vue.use(Vuetify) new Vue({ el: '#app'

Lexical scope/closures in javaScript

阅读更多关于 Lexical scope/closures in javaScript

I understand functions in 'js' have lexical scope (i.e. functions create their environment (scope) when they are defined not when they are executed.) function f1() { var a = 1; f2(); } function f2() { return a; } f1(); // a is not defined When I run just 'f()' it returns the inner function. Which I get, that's what 'return' does! function f() { var b = "barb"; return function() { return b; } } console.log(b); //ReferenceError: b is not defined Why do you get 'ReferenceError: b is not defined?' But doesn't the inner function above have access to it's space, f()'s space etc. Being that 'b' is

Emacs lisp: why does this sexp cause an invalid-function error?

阅读更多关于 Emacs lisp: why does this sexp cause an invalid-function error?

问题 The sexp in question is (((lambda (b) (lambda (a) (+ b a))) 3) 5) which, to me, looks like it should evaluate to 8 , and in other lisps (e.g. Racket) it does, but in elisp it instead throws this error: Debugger entered--Lisp error: (invalid-function ((lambda (b) (lambda (a) (+ b a))) 3)) It appears to be telling me that ((lambda (b) (lambda (a) (+ b a))) 3) Is not a valid function. This seems wrong, because when I evaluate that expression I get (lambda (a) (+ b a)) which looks like a valid

Prevent JavaScript closure from inheriting scope

阅读更多关于 Prevent JavaScript closure from inheriting scope

问题 I am looking for a fancy way to prevent a closure from inheriting surrounding scrope. For example: let foo = function(t){ let x = 'y'; t.bar = function(){ console.log(x); // => 'y' }); }; there are only two ways I know of preventing sharing scope: (1) Use shadow variables: let foo = function(t){ let x = 'y'; t.bar = function(x){ console.log(x); // => '?' }); }; (2) Put the function body somewhere else: let foo = function(t){ let x = 'y'; t.bar = createBar(); }; My question is - does anyone

Lexical scope/closures in javaScript

阅读更多关于 Lexical scope/closures in javaScript

问题 I understand functions in 'js' have lexical scope (i.e. functions create their environment (scope) when they are defined not when they are executed.) function f1() { var a = 1; f2(); } function f2() { return a; } f1(); // a is not defined When I run just 'f()' it returns the inner function. Which I get, that's what 'return' does! function f() { var b = "barb"; return function() { return b; } } console.log(b); //ReferenceError: b is not defined Why do you get 'ReferenceError: b is not defined?