7. Rest parameters | ES6 | JavaScript
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The document discusses rest parameters in ES6, which allow a function to accept an indefinite number of arguments as an array. It explains that rest parameters must be the last part of a function's parameters and are prefixed with three dots. The document compares rest parameters to the arguments object, noting rest parameters can be iterated over like arrays but arguments cannot. It also demonstrates how rest parameters can be destructured to assign array elements to distinct variables in the function body.
![Introduction
Example
function getEmployeeDetails(…rest){
return rest[0] + “ ”+ rest[1] + “ ” + rest[2];
}
getEmployeeDetails( ‘emp01’, ‘PJ’, ‘SSE’ ) // function calling](https://image.slidesharecdn.com/restparams-170904081240/85/7-Rest-parameters-ES6-JavaScript-5-320.jpg)
![Destructuring Rest params
Rest params can be Destructured, that means that their data can be
unpacked into distinct variables.
Syntax
function function_name(…[params]){
// function body
}](https://image.slidesharecdn.com/restparams-170904081240/85/7-Rest-parameters-ES6-JavaScript-7-320.jpg)
![Destructuring Rest params
Example
function getSumOfNumbers(…[a, b, c]){
return a + b + c;
}
getSumOfNumbers( 10, 20, 30 );](https://image.slidesharecdn.com/restparams-170904081240/85/7-Rest-parameters-ES6-JavaScript-8-320.jpg)
7. Rest parameters | ES6 | JavaScript
- 1. Rest Params | ES6 JAGADEESH PATTA ( PJ )
- 2. Agenda Introduction to Rest Parameters Rest params vs arguments object. Destructuring rest params. Live Example
- 3. Introduction The rest parameters allows us to represent an indefinite number of arguments as an array. Rest params of a function prefixed with(…). The rest params index starts with 0 index. Rest params must be last param of function arguments.
- 4. Introduction Syntax function function_name(…restParams){ // function body } function_name( ) // function calling
- 5. Introduction Example function getEmployeeDetails(…rest){ return rest[0] + “ ”+ rest[1] + “ ” + rest[2]; } getEmployeeDetails( ‘emp01’, ‘PJ’, ‘SSE’ ) // function calling
- 6. Rest params vs arguments object Rest params is an instance of array. But arguments object is not an instance of array. We can apply sort, map, forEach operations on rest params But we can’t on arguments object. Arguments object has one feature is called callee property. But rest params doesn’t have it.
- 7. Destructuring Rest params Rest params can be Destructured, that means that their data can be unpacked into distinct variables. Syntax function function_name(…[params]){ // function body }
- 8. Destructuring Rest params Example function getSumOfNumbers(…[a, b, c]){ return a + b + c; } getSumOfNumbers( 10, 20, 30 );
- 9. Any Q ?
- 10. Thank You