Method parseSizeGroup

static/katex/katex.mjs:15541–15586

* Parses a size specification, consisting of magnitude and unit.

(optional)

  parseSizeGroup(optional) {
    let res;
    let isBlank = false;

    if (!optional && this.nextToken.text !== "{") {
      res = this.parseRegexGroup(/^[-+]? *(?:$|\d+|\d+\.\d*|\.\d*) *[a-z]{0,2} *$/, "size");
    } else {
      res = this.parseStringGroup("size", optional);
    }

    if (!res) {
      return null;
    }

    if (!optional && res.text.length === 0) {
      // Because we've tested for what is !optional, this block won't
      // affect \kern, \hspace, etc. It will capture the mandatory arguments
      // to \genfrac and \above.
      res.text = "0pt"; // Enable \above{}

      isBlank = true; // This is here specifically for \genfrac
    }

    const match = /([-+]?) *(\d+(?:\.\d*)?|\.\d+) *([a-z]{2})/.exec(res.text);

    if (!match) {
      throw new ParseError("Invalid size: '" + res.text + "'", res);
    }

    const data = {
      number: +(match[1] + match[2]),
      // sign + magnitude, cast to number
      unit: match[3]
    };

    if (!validUnit(data)) {
      throw new ParseError("Invalid unit: '" + data.unit + "'", res);
    }

    return {
      type: "size",
      mode: this.mode,
      value: data,
      isBlank
    };
  }
  /**
   * Parses an URL, checking escaped letters and allowed protocols.
   */