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separate the caching wrapper from the matcher generator
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@michaelficarra
michaelficarra committed Feb 16, 2023
1 parent d054bcb commit 806c085
Showing 1 changed file with 55 additions and 80 deletions.
135 changes: 55 additions & 80 deletions esquery.js
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Original file line number Diff line number Diff line change
Expand Up @@ -78,80 +78,89 @@ function inPath(node, ancestor, path, fromPathIndex) {
* A WeakMap for holding cached matcher functions for selectors.
* @type {WeakMap<SelectorAST, SelectorMatcher>}
*/
const MATCHER_CACHE = new WeakMap();
const MATCHER_CACHE = typeof WeakMap === 'function' ? new WeakMap : null;

/**
* Create and cache a matcher function for `selector`,
* or return a cached matcher if one already exists.
* Look up a matcher function for `selector` in the cache.
* If it does not exist, generate it with `generateMatcher` and add it to the cache.
* In engines without WeakMap, the caching is skipped and matchers are generated with every call.
* @param {?SelectorAST} selector
* @returns {SelectorMatcher}
*/
function getMatcher(selector) {
if (!selector) {
if (selector == null) {
return () => true;
}

let matcher = MATCHER_CACHE.get(selector);
if (matcher) {
if (MATCHER_CACHE != null) {
let matcher = MATCHER_CACHE.get(selector);
if (matcher != null) {
return matcher;
}
matcher = generateMatcher(selector);
MATCHER_CACHE.set(selector, matcher);
return matcher;
}

return generateMatcher(selector);
}

/**
* Create a matcher function for `selector`,
* @param {?SelectorAST} selector
* @returns {SelectorMatcher}
*/
function generateMatcher(selector) {
switch(selector.type) {
case 'wildcard':
matcher = () => true;
break;
return () => true;

case 'identifier': {
const value = selector.value.toLowerCase();
matcher = (node) => value === node.type.toLowerCase();
break;
return (node) => value === node.type.toLowerCase();
}

case 'field': {
const path = selector.name.split('.');
matcher = (node, ancestry) => {
return (node, ancestry) => {
const ancestor = ancestry[path.length - 1];
return inPath(node, ancestor, path, 0);
};
break;
}

case 'matches': {
const matchers = selector.selectors.map(getMatcher);
matcher = (node, ancestry, options) => {
return (node, ancestry, options) => {
for (let i = 0; i < matchers.length; ++i) {
if (matchers[i](node, ancestry, options)) { return true; }
}
return false;
};
break;
}

case 'compound': {
const matchers = selector.selectors.map(getMatcher);
matcher = (node, ancestry, options) => {
return (node, ancestry, options) => {
for (let i = 0; i < matchers.length; ++i) {
if (!matchers[i](node, ancestry, options)) { return false; }
}
return true;
};
break;
}

case 'not': {
const matchers = selector.selectors.map(getMatcher);
matcher = (node, ancestry, options) => {
return (node, ancestry, options) => {
for (let i = 0; i < matchers.length; ++i) {
if (matchers[i](node, ancestry, options)) { return false; }
}
return true;
};
break;
}

case 'has': {
const matchers = selector.selectors.map(getMatcher);
matcher = (node, ancestry, options) => {
return (node, ancestry, options) => {
let result = false;

const a = [];
Expand All @@ -174,25 +183,23 @@ function getMatcher(selector) {

return result;
};
break;
}

case 'child': {
const left = getMatcher(selector.left);
const right = getMatcher(selector.right);
matcher = (node, ancestry, options) => {
return (node, ancestry, options) => {
if (right(node, ancestry, options)) {
return left(ancestry[0], ancestry.slice(1), options);
}
return false;
};
break;
}

case 'descendant': {
const left = getMatcher(selector.left);
const right = getMatcher(selector.right);
matcher = (node, ancestry, options) => {
return (node, ancestry, options) => {
if (right(node, ancestry, options)) {
for (let i = 0, l = ancestry.length; i < l; ++i) {
if (left(ancestry[i], ancestry.slice(i + 1), options)) {
Expand All @@ -202,119 +209,93 @@ function getMatcher(selector) {
}
return false;
};
break;
}

case 'attribute': {
const path = selector.name.split('.');
switch (selector.operator) {
case void 0:
matcher = (node) => getPath(node, path) != null;
break;
return (node) => getPath(node, path) != null;
case '=':
switch (selector.value.type) {
case 'regexp':
matcher = (node) => {
return (node) => {
const p = getPath(node, path);
return typeof p === 'string' && selector.value.value.test(p);
};
break;
case 'literal': {
const literal = `${selector.value.value}`;
matcher = (node) => literal === `${getPath(node, path)}`;
break;
return (node) => literal === `${getPath(node, path)}`;
}
case 'type':
matcher = (node) => selector.value.value === typeof getPath(node, path);
break;
default:
throw new Error(`Unknown selector value type: ${selector.value.type}`);
return (node) => selector.value.value === typeof getPath(node, path);
}
break;
throw new Error(`Unknown selector value type: ${selector.value.type}`);
case '!=':
switch (selector.value.type) {
case 'regexp':
matcher = (node) => !selector.value.value.test(getPath(node, path));
break;
return (node) => !selector.value.value.test(getPath(node, path));
case 'literal': {
const literal = `${selector.value.value}`;
matcher = (node) => literal !== `${getPath(node, path)}`;
break;
return (node) => literal !== `${getPath(node, path)}`;
}
case 'type':
matcher = (node) => selector.value.value !== typeof getPath(node, path);
break;
default:
throw new Error(`Unknown selector value type: ${selector.value.type}`);
return (node) => selector.value.value !== typeof getPath(node, path);
}
break;
throw new Error(`Unknown selector value type: ${selector.value.type}`);
case '<=':
matcher = (node) => getPath(node, path) <= selector.value.value;
break;
return (node) => getPath(node, path) <= selector.value.value;
case '<':
matcher = (node) => getPath(node, path) < selector.value.value;
break;
return (node) => getPath(node, path) < selector.value.value;
case '>':
matcher = (node) => getPath(node, path) > selector.value.value;
break;
return (node) => getPath(node, path) > selector.value.value;
case '>=':
matcher = (node) => getPath(node, path) >= selector.value.value;
break;
default:
throw new Error(`Unknown operator: ${selector.operator}`);
return (node) => getPath(node, path) >= selector.value.value;
}
break;
throw new Error(`Unknown operator: ${selector.operator}`);
}

case 'sibling': {
const left = getMatcher(selector.left);
const right = getMatcher(selector.right);
matcher = (node, ancestry, options) => {
return right(node, ancestry, options) &&
return (node, ancestry, options) =>
right(node, ancestry, options) &&
sibling(node, left, ancestry, LEFT_SIDE, options) ||
selector.left.subject &&
left(node, ancestry, options) &&
sibling(node, right, ancestry, RIGHT_SIDE, options);
};
break;
}

case 'adjacent': {
const left = getMatcher(selector.left);
const right = getMatcher(selector.right);
matcher = (node, ancestry, options) => {
return right(node, ancestry, options) &&
return (node, ancestry, options) =>
right(node, ancestry, options) &&
adjacent(node, left, ancestry, LEFT_SIDE, options) ||
selector.right.subject &&
left(node, ancestry, options) &&
adjacent(node, right, ancestry, RIGHT_SIDE, options);
};
break;
}

case 'nth-child': {
const nth = selector.index.value;
const right = getMatcher(selector.right);
matcher = (node, ancestry, options) => {
return right(node, ancestry, options) &&
return (node, ancestry, options) =>
right(node, ancestry, options) &&
nthChild(node, ancestry, nth, options);
};
break;
}

case 'nth-last-child': {
const nth = -selector.index.value;
const right = getMatcher(selector.right);
matcher = (node, ancestry, options) => {
return right(node, ancestry, options) &&
return (node, ancestry, options) =>
right(node, ancestry, options) &&
nthChild(node, ancestry, nth, options);
};
break;
}

case 'class': {
const name = selector.name.toLowerCase();
matcher = (node, ancestry) => {
return (node, ancestry) => {
switch(name){
case 'statement':
if(node.type.slice(-9) === 'Statement') return true;
Expand All @@ -339,15 +320,10 @@ function getMatcher(selector) {
}
throw new Error(`Unknown class name: ${selector.name}`);
};
break;
}
}

if (!matcher) {
throw new Error(`Unknown selector type: ${selector.type}`);
}
MATCHER_CACHE.set(selector, matcher);
return matcher;
throw new Error(`Unknown selector type: ${selector.type}`);
}

/**
Expand Down Expand Up @@ -377,8 +353,7 @@ function matches(node, selector, ancestry, options) {
if (!node) { return false; }
if (!ancestry) { ancestry = []; }

const matcher = getMatcher(selector);
return matcher(node, ancestry, options);
return getMatcher(selector)(node, ancestry, options);
}

/**
Expand Down

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