Front-end intern interview questions 2-1

Event modifiers :

stop:  prevents the event from bubbling, which is equivalent to calling the event.stopPropagation method

prevent:  Prevent the default behavior of the event, which is equivalent to calling the event.preventDefault method

 self: trigger the handler only when  event.target is the current element itself

once: After the event is bound, it can only be triggered once, and it will not be triggered the second time

capture: causes the event to fire from the top level containing this element down

passive: On the mobile side, when we are listening to element scrolling events, the onscroll event will always be triggered and our web page will become stuck, so when we use this modifier, it is equivalent to adding a .lazy modifier to the onscroll event

native: Let the component listen to the native event of the root element  like a built-in HTML tag, otherwise v-on on the component  will only listen to custom events

Mouse button modifiers : left left click right right click middle middle click   

Keyboard modifiers :  keyCode contains

Common keys (enter, tab, delete, space, esc, up...)

System modifier keys (ctrl, alt, meta, shift...)

v-bind modifier :

async: can perform a two-way binding on props

props :  Set custom tag attributes to avoid exposing data and preventing HTML structure from being polluted

camel:  Change the naming to camel case, such as converting  the view-Box attribute name to  viewBox

ref:  ref  is used to register reference information to elements or subcomponents. Reference information will be registered on the  $refs  object of the parent component. If used on a normal DOM element, the reference points to the DOM element; if used on a child component, the reference points to the component instance .

axios :inbrowsers andnode.js. Supports creating XML requests from browsers, supports nodejs to send http requests, supports conversion of request and response data, and supports automatic conversion of JSON

Routing parameters :params, query, $router.push()

$route and $ router: 

$router is an example application of vuerouter, which mainly implements routing jumps. If you want to jump to different paths, use the his.$router.push method .

$route is a route object for jumping. Each route will have a $route object, which is a local object, and can obtain the corresponding name, path, params, query, etc.

Reference data types and primitive data types:

Reference data type: the address is stored in the stack, and the data is stored in the heap; Object, Array, Function, Data, etc.

Basic data types: stored in the stack; Number, String, Boolean, Null and Undefined.

V ue data binding principle:

We need a listener Observer to set the set function for all properties. If the property changes, all subscribers Watcher should be notified. And these Watchers are uniformly stored in the message subscriber Dep, which is more convenient for unified management. After receiving the notification from Dep, Watcher performs corresponding operations to update the view.

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Origin blog.csdn.net/Ct130429/article/details/122123499