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WedgepostMessage It is commonly used in embedded iframe or Web Workers for cross page (thread) message communication. Similar shadows can be seen in some other development environments, such as Chrome plug-in environment, Electron environment, sigma plug-in, etc.In recent work, we often deal with iframe and Web Workers, deal with pages and embe ...

abstract Computer based students are probably familiar with the word pipeline. Especially in Linux system, pipeline operator has been widely used and has brought great convenience to our transformation. The scaffold "gulp" noted in the front-end field is also famous for its pipeline operation. Today, let's take a step-by-step look a ...

When learning becomes a habit, knowledge becomes common sense. Thank you for your attention, likes, collections and comments.The new video and articles will be sent to WeChat official account for the first time. Li YongningThe article has been included in github warehouse liyongning/blog , welcome to Watch and Star.prefaceAs mentioned earlier, ...

1. Changes in life cycle: 3 X (upper) 2 X (bottom) It's not hard to see, vue3 0 and vue2 The life cycle function between 0 changes during destruction: beforeDestroy --> beforeUnmount destroyed --> unmounted Other differences mainly lie in the language used in writing stay ts Used in class Class component writing can refer to vue-c ...

Pinia pinia is now the official state library of Vue. It is applicable to vue2 and vue3. This paper only describes the writing method of vue3. image-20220217155244154.png Advantages of pinia Compared with the previous vuex, pinia has the following advantages Simpler writing method, clearer and concise code, and support the syntax of &qu ...

1, Type inference In the previous learning process, we need to write type annotations when defining basic types of variables. Although this can clearly indicate the data type of variables, it is really troublesome to write. TS also helps us take this problem into consideration. In most cases, TS will automatically deduce the type of variable a ...

Advanced chapter of Lesson 8_ Indexes I MySQL Linux Installation 1. Prepare Linux server CentOS 7.0 Final shell connection server 2. Download MySQL installation package for Linux www.mysql.com Download Community Edition (free) 3. Upload MySQL installation package 4. Create a directory and unzip it mkdir mysql tar -xvf mysql-8.0.rpm-bu ...

Lesson 4 Basic _ constraint 1. Summary 1. Concepts Rules that act on fields in a table to restrict data stored in the table. 2. Purpose Ensure that the data is correct, valid and complete. 3. Classification constraintdescribeKeywordNon-empty constraintRestrict the field to data that cannot be nullNOT NULLUnique ConstraintEnsure that all ...

Lesson 5 Basic _ multi-table query 1. Multi-table relations In project development, when designing database table structure, the table structure will be analyzed and designed according to the business requirements and the relationship between business modules. Because business is related to each other, there are also various connections among ...

1, In Vue3, the difference between the use of rouyou and Vue2 First, if you habitually use this$ Router, you will definitely get an error report, because Vue3 does not have this and uses a new API, so we need to introduce the function useRouter in router at this time import { defineComponent, reactive} from "vue" import { useRouter } from "vu ...