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88 lines
2.0 KiB
88 lines
2.0 KiB
var _ = require("underscore");
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var ast = require("./ast");
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function simplify(nodes) {
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return collapse(removeEmpty(nodes));
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}
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function collapse(nodes) {
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var children = [];
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nodes.map(collapseNode).forEach(function(child) {
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appendChild(children, child);
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});
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return children;
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}
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function collapseNode(node) {
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return collapsers[node.type](node);
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}
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var collapsers = {
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element: collapseElement,
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text: identity,
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forceWrite: identity
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};
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function collapseElement(node) {
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return ast.elementWithTag(node.tag, collapse(node.children));
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}
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function identity(value) {
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return value;
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}
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function appendChild(children, child) {
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var lastChild = children[children.length - 1];
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if (child.type === "element" && !child.tag.fresh && lastChild && lastChild.type === "element" && child.tag.matchesElement(lastChild.tag)) {
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if (child.tag.separator) {
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appendChild(lastChild.children, ast.text(child.tag.separator));
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}
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child.children.forEach(function(grandChild) {
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// Mutation is fine since simplifying elements create a copy of the children.
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appendChild(lastChild.children, grandChild);
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});
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} else {
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children.push(child);
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}
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}
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function removeEmpty(nodes) {
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return flatMap(nodes, function(node) {
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return emptiers[node.type](node);
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});
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}
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function flatMap(values, func) {
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return _.flatten(_.map(values, func), true);
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}
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var emptiers = {
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element: elementEmptier,
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text: textEmptier,
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forceWrite: neverEmpty
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};
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function neverEmpty(node) {
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return [node];
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}
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function elementEmptier(element) {
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var children = removeEmpty(element.children);
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if (children.length === 0 && !ast.isVoidElement(element)) {
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return [];
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} else {
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return [ast.elementWithTag(element.tag, children)];
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}
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}
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function textEmptier(node) {
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if (node.value.length === 0) {
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return [];
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} else {
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return [node];
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}
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}
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module.exports = simplify;
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