REST API Experiments

In this document we explore how to fetch JSON data from the web and display it in various ways. We also make use of global variables, showing their content in an HTML template, and rendering blocks conditionally. Source of the data: https://alternative.me/crypto/fear-and-greed-index

Cryptocurrency Fear and Greed Index

In this first example we want to see last 15 days of the F&G index The data is downloaded from https://alternative.me API

we want to display the date on the x-axis
on the y-axis should be the value of the F&G index
what to display as the end-of-line label
outer width, in pixels
outer height, in pixels
we know the range of the y-axis (it's %) so let's indicate it

We download the data and process it with some javascript to feed the chart

Let's extract sentiment from the data, as a variable so we can use it later

Check below how we display the sentiment variable previously defined, via a HTML block

We can even use "if" branches to process and display things conditionally

Cryptocurrency prices

Now we want to display the current prices

we want price on x-axis
we want the name of the coin on y-axis
the left margin, in pixels

This time we fetch the API for the prices

We can use the map operation to keep only a subset of the properties

We want to show the cryptocurrencies sorted by price (descending)

Now we save this data because we want to re-use it in the next step too

At last we choose a table to list the cryptocurrencies

Let's specify which columns we want in the table, first an index

After the index we want the cryptocurrency name

And after the name, its price (notice how the $ currency symbol is added)

Let's load the previously saved data