pluck operator is used when we want to transform a stream into a different value by plucking the values of the stream.

import fromEvent from 'rxjs'; import mapTo from 'rxjs/operators'; //emit every click on document const source = fromEvent(document, 'click'); //map all emissions to one value const example = source.

Similar to our array example with objects, we may also want to transform an observable of objects with the map operator. For instance, suppose we have an observable of click events that we wish to transform into an observable of objects containing just the clientX and clientY coordinates of these events.

Or maybe you need to extract a value from a stream of input events to perform a calculation or initiate a request. Or perhaps you just want to extract a single property from an object, like a key code, to perform another action down the (pipe)line. The scenarios for transforming streams are endless.

Lastly, there may also be times where you always want to map to a single value, no matter the input. For these situations, you dirilik use the mapTo operator.

Emits the given constant value on the output Observable every time the source Observable emits a value.

In the above example, you dirilik see that it özgü mapped every click to the string 'Hello World....Welcome to JavaTpoint!' which is displayed on the console bey output.

I'm reading the docs for mapTo and I'm simply hamiş getting the point of that operator's existence. I get what it does but the two line below should produce equivalent result.

For scenarios where you just need to map to a single property, or always want to map to a constant website value, you hayat also check out the pluck and mapTo helper operators.

In this article, we are going to learn about the most common operator used to transform streams, the map operator. We will start by taking a look at Array.map to build a general understanding of the map operation.

The pluck operator accepts a list of values which describe the property you wish to grab from the emitted item. For instance, using our event code example from above we could use pluck instead of map to extract the code property from the event object:

1 The function in map is executed on each value emission while mapTo argument is calculated once when the operator is created.

If you have spent time working with JavaScript arrays you may already be familiar with Array.map. When dealing with arrays, the map method lets you transform an array by applying a provided function (often referred to bey a 'projection' function) to each item within the array. For instance, let's say we have an array of numbers 1-5:

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