Custom Tags

• LiquidJS: Tags

module.exports = function (eleventyConfig) {
	// Usage: {% uppercase myVar %} where myVar has a value of "alice"
	// Usage: {% uppercase "alice" %}
	eleventyConfig.addLiquidTag("uppercase", function (liquidEngine) {
		return {
			parse: function (tagToken, remainingTokens) {
				this.str = tagToken.args; // myVar or "alice"
			},
			render: async function (scope, hash) {
				// Resolve variables
				var str = await this.liquid.evalValue(this.str, scope); // "alice"

				// Do the uppercasing
				return str.toUpperCase(); // "ALICE"
			},
		};
	});
};

See all of the built-in tag implementations for LiquidJS.

• Nunjucks: Custom Tags

module.exports = function (eleventyConfig) {
	// Usage: {% uppercase myVar %} where myVar has a value of "alice"
	// Usage: {% uppercase "alice" %}
	eleventyConfig.addNunjucksTag("uppercase", function (nunjucksEngine) {
		return new (function () {
			this.tags = ["uppercase"];

			this.parse = function (parser, nodes, lexer) {
				var tok = parser.nextToken();

				var args = parser.parseSignature(null, true);
				parser.advanceAfterBlockEnd(tok.value);

				return new nodes.CallExtensionAsync(this, "run", args);
			};

			this.run = function (context, myStringArg, callback) {
				let ret = new nunjucksEngine.runtime.SafeString(
					myStringArg.toUpperCase()
				);
				callback(null, ret);
			};
		})();
	});
};