Babel plugin to optimize tagged templates by inlining string/number/boolean values.

babel-plugin-optimize-tagged-templates.js

module.exports = (babel, options = {}) => {
  const { types: t } = babel;
  
  return {
    name: "optimize-tagged-templates",
    visitor: {
      TemplateLiteral(path) {
        for (let i=0; i<path.node.expressions.length; i++) {
          const expr = path.node.expressions[i];
          let isLiteral = t.isStringLiteral(expr);
          if (options.numbers!==false && t.isNumericLiteral(expr)) {
            isLiteral = true;
          }
          if (options.booleans!==false && t.isBooleanLiteral(expr)) {
            isLiteral = true;
          }
          if (isLiteral) {
            const str = expr.value;
            const before = path.node.quasis[i].value;
            const after = path.node.quasis[i+1].value;
            before.raw += str + after.raw;
            before.cooked += str + after.cooked;
            path.node.expressions.splice(i, 1);
            path.node.quasis.splice(i+1, 1);
          }
        }
      }
    }
  };
};

package.json

{
  "name": "babel-plugin-optimize-tagged-templates",
  "main": "babel-plugin-optimize-tagged-templates.js",
  "version": "0.1.0"
}