A javascript tool for adjusting size, leading, and grades to cast continuously responsive typography. It works over your current CSS as a progressive enhancement.

The script calculates your setting based on minimum and maximum values for font size, line height, variable grades, and container width:

• minimum/maximum font size
• minimum/maximum line height
• minimum/maximum container width
• minimum/maximum grades (variable fonts only)

1. Include the main script and
2. target elements using JS notation:

<script src="textblock.min.js"></script>

<script>
  Textblock([{
    target: ".some-element"
  }]);
</script>

1. Add to modules with npm install --save textblock,
2. include the module, and
3. apply to elements within componentDidMount() as needed:

import Textblock from 'textblock';

componentDidMount() {
  Textblock([{
    target: ".some-element"
  }]);
}

• target (required  ): The element that should be resized ".your‑class", "#some-id p"
• minWidth: default 320
• maxWidth: default 960
• minWidth_FontSize: default 1.0
• maxWidth_FontSize: default 1.8
• minWidth_LineHeight: default 1.33 (unitless values only)
• maxWidth_LineHeight: default 1.25 (unitless values only)
• minWidth_VariableGrade: A variable font weight for the small size, for example 450
• maxWidth_VariableGrade: A variable font weight for the large size, i.e. 400
• container: The container width to measure. Defaults to "parent" and can alternately be set to "self".
• fontSize_Units: default em

For a better sense of context, set your root em to 10px with html { font-size: 62.5%; }. This makes your em units base 10 so 2.4em = 24px. But any number will do because once you start adjusting the min/max numbers, the experience is more visual than calculated. And if you prefer a more scientific approach, Textblock gives you the control you need for setting systems like modular scales.

If you’re using variable fonts, the minWidth_VariableGrade / maxWidth_VariableGrade parameters provide a way to simulate grades (micro-variations in weight to set smaller sizes slightly bolder).

Textblock([{
 target: ".some-class",
 minWidth: 280,
 maxWidth: 800,
 minWidth_FontSize: 1.9,
 maxWidth_FontSize: 2.6,
 minWidth_LineHeight: 1.33,
 maxWidth_LineHeight: 1.25,
 minWidth_VariableGrade: 366,
 maxWidth_VariableGrade: 300,
 container: "self",
 fontSize_Units: "rem"
}]);

Textblock([
 {
  target: ".some-class",
  minWidth_FontSize: 1.9,
  maxWidth_FontSize: 2.6
 },
 {
  target: ".another-class",
  minWidth_FontSize: 2.4,
  maxWidth_FontSize: 3.6,
  minWidth_VariableGrade: 450,
  maxWidth_VariableGrade: 400,
  container: "self"
 }
]);