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author | Divay Prakash <divayprakash@users.noreply.github.com> | 2019-11-24 12:38:47 +0530 |
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committer | GitHub <noreply@github.com> | 2019-11-24 12:38:47 +0530 |
commit | ede3cc5484efe1966c0988a5b5fe6b7514205ce9 (patch) | |
tree | 10616a60734a9a896bfbbcca9578c36e390a1082 /javascript.html.markdown | |
parent | 3d75c100b4b79d78786860effb9dbaea1620e4ce (diff) | |
parent | f0ce8b2ba2156c8f7e10f114245cc92f757fb6d1 (diff) |
Merge branch 'master' into patch-4
Diffstat (limited to 'javascript.html.markdown')
-rw-r--r-- | javascript.html.markdown | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/javascript.html.markdown b/javascript.html.markdown index c466c09b..ce9772ca 100644 --- a/javascript.html.markdown +++ b/javascript.html.markdown @@ -586,6 +586,48 @@ if (Object.create === undefined){ // don't overwrite it if it exists return new Constructor(); }; } + +// ES6 Additions + +// The "let" keyword allows you to define variables in a lexical scope, +// as opposed to a block scope like the var keyword does. +let name = "Billy"; + +// Variables defined with let can be reassigned new values. +name = "William"; + +// The "const" keyword allows you to define a variable in a lexical scope +// like with let, but you cannot reassign the value once one has been assigned. + +const pi = 3.14; + +pi = 4.13; // You cannot do this. + +// There is a new syntax for functions in ES6 known as "lambda syntax". +// This allows functions to be defined in a lexical scope like with variables +// defined by const and let. + +const isEven = (number) => { + return number % 2 === 0; +}; + +isEven(7); // false + +// The "equivalent" of this function in the traditional syntax would look like this: + +function isEven(number) { + return number % 2 === 0; +}; + +// I put the word "equivalent" in double quotes because a function defined +// using the lambda syntax cannnot be called before the definition. +// The following is an example of invalid usage: + +add(1, 8); + +const add = (firstNumber, secondNumber) => { + return firstNumber + secondNumber; +}; ``` ## Further Reading |