Computer Science theory definitions

• Singleton

  • Restrict the instantiation of a class to one “single” instance (see the wiki article)
  • This is useful when exactly one object is needed to coordinate actions across the system.

• debounce:

  • it limits the rate at which a function can fire
  • In redux-saga is non-blocking.

• idempotent: When applying a function multiple times, the state won’t change after applying it the first time.

  • A function we can retry several times until it works! Yeah!
• idiomatic: Idiomatic in the context of programming can usually be defined as “the most natural way to express something in a language”

• imperative vs. declarative

  See the article which compares imperative vs. declarative

literal vs statement vs expression

literals

Representing a value within source code.

• "foo" (a string)
• true (a boolean)
• …

Not literals:

• std::cout (an identifier - refer to a value in memory)
• foo = 0; (a statement)
• 1+2 (an expression)

Taken from this SO answer.

Statement vs. Expression

• Statements are everything that can make up a line (or several lines) of Python code. Note that expressions are statements as well.
• Expressions can be reduced to some kind of “value”

Taken from this excellent answer concerning python.

Examples

Expressions

Something that evaluates to a value.

• 3 + 5
• function() {} because every function will return something. With no return specified, a function expression will return undefined.
• yield* is an expression, not a statement — so it evaluates to a value.

• In the haskell article I read the following line:

  Haskell’s if is an expression that must return a value, and not a statement.

Statements

JavaScript

• if/else clause and switch/case
• return
• import and export
• with

See this article from Axel Rauschmayer for more details.

Compiled vs. transpiled

• Great article