pagedjs/src/modules/generated-content/string-sets.js

Chunks up a document into paged media flows and applies print styles

import Handler from "../handler.js";
import csstree from "css-tree";
import { cleanPseudoContent } from "../../utils/css.js";

class StringSets extends Handler {
	constructor(chunker, polisher, caller) {
		super(chunker, polisher, caller);

		this.stringSetSelectors = {};
		this.type;
		// pageLastString = last string variable defined on the page 
		this.pageLastString;

	}
	
	onDeclaration(declaration, dItem, dList, rule) {
		if (declaration.property === "string-set") {
			let selector = csstree.generate(rule.ruleNode.prelude);

			let identifier = declaration.value.children.first().name;

			let value;
			csstree.walk(declaration, {
				visit: "Function",
				enter: (node, item, list) => {
					value = csstree.generate(node);
				}
			});

			this.stringSetSelectors[identifier] = {
				identifier,
				value,
				selector
			};
		}
	}

	onContent(funcNode, fItem, fList, declaration, rule) {

		if (funcNode.name === "string") {
			let identifier = funcNode.children && funcNode.children.first().name;
			this.type = funcNode.children.last().name;
			funcNode.name = "var";
			funcNode.children = new csstree.List();

 
			if(this.type === "first" || this.type === "last" || this.type === "start" || this.type === "first-except"){
				funcNode.children.append(
					funcNode.children.createItem({
						type: "Identifier",
						loc: null,
						name: "--pagedjs-string-" + this.type + "-" + identifier
					})
				);
			}else{
				funcNode.children.append(
					funcNode.children.createItem({
						type: "Identifier",
						loc: null,
						name: "--pagedjs-string-first-" + identifier
					})
				);
			}
		}
	}

	afterPageLayout(fragment) {

	
		if ( this.pageLastString === undefined )
		{
			this.pageLastString = {};
		}
	
		
		for (let name of Object.keys(this.stringSetSelectors)) {
	
			let set = this.stringSetSelectors[name];
			let selected = fragment.querySelectorAll(set.selector);

			// Get the last found string for the current identifier
			let stringPrevPage = ( name in this.pageLastString ) ? this.pageLastString[name] : "";

			let varFirst, varLast, varStart, varFirstExcept;

			if(selected.length == 0){
				// if there is no sel. on the page
				varFirst = stringPrevPage;
				varLast = stringPrevPage;
				varStart = stringPrevPage;
				varFirstExcept = stringPrevPage;
			}else{

				selected.forEach((sel) => {
					// push each content into the array to define in the variable the first and the last element of the page.
					this.pageLastString[name] = selected[selected.length - 1].textContent;
				
				});	

				/* FIRST */
	
				varFirst = selected[0].textContent;


				/* LAST */

				varLast = selected[selected.length - 1].textContent;


				/* START */

				// Hack to find if the sel. is the first elem of the page / find a better way 
				let selTop = selected[0].getBoundingClientRect().top;
				let pageContent = selected[0].closest(".pagedjs_page_content");
				let pageContentTop = pageContent.getBoundingClientRect().top;

				if(selTop == pageContentTop){
					varStart = varFirst;
				}else{
					varStart = stringPrevPage;
				}

				/* FIRST EXCEPT */

				varFirstExcept = "";
				
			}

			fragment.style.setProperty(`--pagedjs-string-first-${name}`, `"${cleanPseudoContent(varFirst)}`);
			fragment.style.setProperty(`--pagedjs-string-last-${name}`, `"${cleanPseudoContent(varLast)}`);
			fragment.style.setProperty(`--pagedjs-string-start-${name}`, `"${cleanPseudoContent(varStart)}`);
			fragment.style.setProperty(`--pagedjs-string-first-except-${name}`, `"${cleanPseudoContent(varFirstExcept)}`);
			
	
		}
	}
	

}



export default StringSets;