SyntaxError: Invalid character '\u8224' about d3-geo-projection

[mbostock]

In past versions you needed to ensure that d3-geo-projection was loaded using the UTF-8 charset or the unicode variable names would not get parsed directly and result in a SyntaxError. That means one of these must be true:

• The server must serve d3.geo.projection.js with the charset UTF-8 (alas does not apply to GitHub Pages and thus d3js.org).
• The page must have a <meta charset="utf-8"> in the head before the script is loaded.
• The script element must have a charset="utf-8" attribute.

For example:

<script src="d3.geo.projection.js" charset="utf-8"></script>

Since d3-geo-projection 1.0 (and D3 4.0), the code is written exclusively in ASCII so this is no longer a requirement.