This question already has answers here :
As people already answered. This is object destructuring
Simple example: const contact = {name: 'John', email: 'john@doe.com'}
With ES6 you can do const {email} = contact; //email = contact.email
In case you want to name the variable differently, it would be:
const {email: mailbox} = contact //equivalent to mailbox = contact.email;
Back to the original question: {intl: { formatMessage }, } = this.context
=> {formatMessage} = this.context.intl => formatMessage = this.context.intl.formatMessage
What does this line of code mean? const {"intl , What does const mean in following line? float& operator()(int &i, int &j) const;. Can someone explain this to me? Also, if we change the position of const , what Definition - What does Const mean? Const is programming syntax that is used to declare a constant variable in languages like C. This is one way of creating a variable that will be used once or many times in code. A constant variable is one that will not change after the program is complied.
The code that you have is, actually a representation of the following code,
const formatMessage = this.context.intl.formatMessage
You can read about object destructuring to know more about it.
What does const mean in following line of code?, In computer programming, a constant is a value that cannot be altered by the program during Because it can be difficult to maintain code where all values are written literally, a keyword qualifier such as const , constant , or final , meaning that its value will be set at compile time and should not be changeable at runtime. For pointer and reference types, the meaning of const is more complicated – either the pointer itself, or the value being pointed to, or both, can be const. Further, the syntax can be confusing. A pointer can be declared as a const pointer to writable value, or a writable pointer to a const value, or const pointer to const value.
This simply means that this.context contains a structure similar to this
this.context = {
intl:{
formatMessage: // This has a value let's say "Hello"
},
//Other key-value pairs could be contained in the context object }
This line of code is a shorthand syntax telling you that only the formatMessage "this.context"
Constant (computer programming), In the C, C++, D, JavaScript and Julia programming languages, const is a type qualifier: a In these cases, the logical meaning (state) of the object is unchanged, but the object is not physically constant since In the above code, the implicit " this " pointer to Set() has the type " C *const "; whereas the " this " pointer to Get() The keyword const is a little misleading. It does NOT define a constant value. It defines a constant reference to a value. Because of this, we cannot change constant primitive values, but we can change the properties of constant objects.
const (computer programming), The second line defines the function: const x _ = x. That's the only possible definition; all const can do is const is a keyword. More specifically, const is a type qualifier. Type qualifiers are part of C types. In the type int const, const is a type qualifier, and int is a type specifier. Here, const qualifies the type int. Qualifiers change the semantics of the type in some way. Other type qualifiers include volatile and restrict.
What does this Haskell code mean? [code haskell] const :: a -> b->a , Your job is to write a subroutine that calculates the sales tax due on the sale of a You could use the following line of code to define a symbolic constant for use in of the definition simply assigns the numeric value for the symbolic constant . Looking for the definition of CONST? Find out what is the full meaning of CONST on Abbreviations.com! 'Constant' is one option -- get in to view more @ The Web's largest and most authoritative acronyms and abbreviations resource.
Visual Basic .Net Primer Plus, A constant is a value that cannot be altered by the program during normal execution the constants used for initializing a variable and constants used in lines of code: Technically, Python does not support named constants, meaning that it is The phrase “lines of code” (LOC) is a metric generally used to evaluate a software program or codebase according to its size. It is a general identifier taken by adding up the number of lines of code used to write a program. LOC is used in various ways to assess a project, and there is a debate on how effective this measurement is.
Comments Look out for object destructuring. it means const formatMessage = this.context.intl.formatMessage, check MDN Doc for more details thank you @Rajaprabhu Aravindasamy
