How to Load Data from CSV Files in D3 v5 Asynchronously?

Loading Data from CSV Files in D3 v5

In D3 v5, loading data from a CSV file requires a slightly different approach compared to v4. Here's how it works:

D3 v5 Data Loading

In v5, D3 uses the Fetch API, which returns a Promise. This necessitates updating your code to handle asynchronous data loading. For example:

<code class="javascript">d3.csv("data/dataset.csv")
  .then(function(data) {
    // Data is now available within the `data` variable
    // Perform your chart or visualization operations here
  })
  .catch(function(error) {
    // Handle data loading errors
  });</code>

Comparison with D3 v4

In D3 v4, data loading utilized the XMLHttpRequest method, which didn't return a Promise. As a result, your code could look like:

<code class="javascript">d3.csv("data/dataset.csv", function(data) {
    // Whole data set available in the `data` variable
    // Draw your chart here
});</code>

Async Nature of Data Loading

Remember that CSV data loading is asynchronous. Therefore, it's crucial to ensure that your chart's code is executed within the data loading function to avoid premature execution before the data is ready.

The above is the detailed content of How to Load Data from CSV Files in D3 v5 Asynchronously?. For more information, please follow other related articles on the PHP Chinese website!