The state variable in the store mentioned in vuex can only be displayed to submit changes through commit? Why is it normal for me to assign values directly?

official documentation: you cannot directly change the state in store. The only way to change the state in store is to commit the mutation explicitly. But why can I modify the value in state directly?
store: 

state={  
     testArr:[
     {"test":1},
     {"test":2}
     ],
     testNum:0
   // testNum
   };

I have a place in div in component A that renders
data through {{this.$store.state.testNum}}, and then in component B"s script,
directly through the assignment statement without warning or error, and the data in component An also changes console to see the corresponding change in this.$store.
does not modify the value of state
this.$store.state.testNum=10 through a mutation method of this.$store.commit.
this.$store.state.testArr [0] .test = 10

console.log (this.$store.state); / /

what does this mean? Or is there a problem with my understanding? Thank you in advance! ~

Node.js vuex vue.js
Jun.14,2022

of course, you can change the value in state with this.$store.state, because this is where the vuex stores the value, but it is generally not done, because it is uncontrollable for the data. Generally, an error warning will be generated in the development environment. As follows

clipboard.png
vuexvuewatch

clipboard.png
state

clipboard.png

mutation

:
image.png

:
scriptthis.$store.state.testArr[0].test=999;999

image.png 

  https://blog.csdn.net/qq_37024887/article/details/104972020

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