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Add support for custom visitor keys. (#112)
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@ota-meshi
ota-meshi committed Feb 2, 2021
1 parent 74a70ac commit 365ed15
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Showing 5 changed files with 356 additions and 40 deletions.
133 changes: 93 additions & 40 deletions esquery.js
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Expand Up @@ -64,17 +64,29 @@ function inPath(node, ancestor, path) {
}
}

/**
* @callback TraverseOptionFallback
* @param {external:AST} node The given node.
* @returns {string[]} An array of visitor keys for the given node.
*/
/**
* @typedef {object} ESQueryOptions
* @property { { [nodeType: string]: string[] } } [visitorKeys] By passing `visitorKeys` mapping, we can extend the properties of the nodes that traverse the node.
* @property {TraverseOptionFallback} [fallback] By passing `fallback` option, we can control the properties of traversing nodes when encountering unknown nodes.
*/

/**
* Given a `node` and its ancestors, determine if `node` is matched
* by `selector`.
* @param {?external:AST} node
* @param {?SelectorAST} selector
* @param {external:AST[]} [ancestry=[]]
* @param {ESQueryOptions} [options]
* @throws {Error} Unknowns (operator, class name, selector type, or
* selector value type)
* @returns {boolean}
*/
function matches(node, selector, ancestry) {
function matches(node, selector, ancestry, options) {
if (!selector) { return true; }
if (!node) { return false; }
if (!ancestry) { ancestry = []; }
Expand All @@ -94,19 +106,19 @@ function matches(node, selector, ancestry) {
}
case 'matches':
for (const sel of selector.selectors) {
if (matches(node, sel, ancestry)) { return true; }
if (matches(node, sel, ancestry, options)) { return true; }
}
return false;

case 'compound':
for (const sel of selector.selectors) {
if (!matches(node, sel, ancestry)) { return false; }
if (!matches(node, sel, ancestry, options)) { return false; }
}
return true;

case 'not':
for (const sel of selector.selectors) {
if (matches(node, sel, ancestry)) { return false; }
if (matches(node, sel, ancestry, options)) { return false; }
}
return true;

Expand All @@ -117,27 +129,28 @@ function matches(node, selector, ancestry) {
estraverse.traverse(node, {
enter (node, parent) {
if (parent != null) { a.unshift(parent); }
if (matches(node, sel, a)) {
if (matches(node, sel, a, options)) {
collector.push(node);
}
},
leave () { a.shift(); },
fallback: 'iteration'
keys: options && options.visitorKeys,
fallback: options && options.fallback || 'iteration'
});
}
return collector.length !== 0;

}
case 'child':
if (matches(node, selector.right, ancestry)) {
return matches(ancestry[0], selector.left, ancestry.slice(1));
if (matches(node, selector.right, ancestry, options)) {
return matches(ancestry[0], selector.left, ancestry.slice(1), options);
}
return false;

case 'descendant':
if (matches(node, selector.right, ancestry)) {
if (matches(node, selector.right, ancestry, options)) {
for (let i = 0, l = ancestry.length; i < l; ++i) {
if (matches(ancestry[i], selector.left, ancestry.slice(i + 1))) {
if (matches(ancestry[i], selector.left, ancestry.slice(i + 1), options)) {
return true;
}
}
Expand Down Expand Up @@ -171,29 +184,29 @@ function matches(node, selector, ancestry) {
throw new Error(`Unknown operator: ${selector.operator}`);
}
case 'sibling':
return matches(node, selector.right, ancestry) &&
sibling(node, selector.left, ancestry, LEFT_SIDE) ||
return matches(node, selector.right, ancestry, options) &&
sibling(node, selector.left, ancestry, LEFT_SIDE, options) ||
selector.left.subject &&
matches(node, selector.left, ancestry) &&
sibling(node, selector.right, ancestry, RIGHT_SIDE);
matches(node, selector.left, ancestry, options) &&
sibling(node, selector.right, ancestry, RIGHT_SIDE, options);
case 'adjacent':
return matches(node, selector.right, ancestry) &&
adjacent(node, selector.left, ancestry, LEFT_SIDE) ||
return matches(node, selector.right, ancestry, options) &&
adjacent(node, selector.left, ancestry, LEFT_SIDE, options) ||
selector.right.subject &&
matches(node, selector.left, ancestry) &&
adjacent(node, selector.right, ancestry, RIGHT_SIDE);
matches(node, selector.left, ancestry, options) &&
adjacent(node, selector.right, ancestry, RIGHT_SIDE, options);

case 'nth-child':
return matches(node, selector.right, ancestry) &&
return matches(node, selector.right, ancestry, options) &&
nthChild(node, ancestry, function () {
return selector.index.value - 1;
});
}, options);

case 'nth-last-child':
return matches(node, selector.right, ancestry) &&
return matches(node, selector.right, ancestry, options) &&
nthChild(node, ancestry, function (length) {
return length - selector.index.value;
});
}, options);

case 'class':
switch(selector.name.toLowerCase()){
Expand Down Expand Up @@ -224,19 +237,53 @@ function matches(node, selector, ancestry) {
throw new Error(`Unknown selector type: ${selector.type}`);
}

/**
* Get visitor keys of a given node.
* @param {external:AST} node The AST node to get keys.
* @param {ESQueryOptions|undefined} options
* @returns {string[]} Visitor keys of the node.
*/
function getVisitorKeys(node, options) {
const nodeType = node.type;
if (options && options.visitorKeys && options.visitorKeys[nodeType]) {
return options.visitorKeys[nodeType];
}
if (estraverse.VisitorKeys[nodeType]) {
return estraverse.VisitorKeys[nodeType];
}
if (options && typeof options.fallback === 'function') {
return options.fallback(node);
}
// 'iteration' fallback
return Object.keys(node).filter(function (key) {
return key !== 'type';
});
}


/**
* Check whether the given value is an ASTNode or not.
* @param {any} node The value to check.
* @returns {boolean} `true` if the value is an ASTNode.
*/
function isNode(node) {
return node !== null && typeof node === 'object' && typeof node.type === 'string';
}

/**
* Determines if the given node has a sibling that matches the
* given selector.
* @param {external:AST} node
* @param {SelectorSequenceAST} selector
* @param {external:AST[]} ancestry
* @param {Side} side
* @param {ESQueryOptions|undefined} options
* @returns {boolean}
*/
function sibling(node, selector, ancestry, side) {
function sibling(node, selector, ancestry, side, options) {
const [parent] = ancestry;
if (!parent) { return false; }
const keys = estraverse.VisitorKeys[parent.type];
const keys = getVisitorKeys(parent, options);
for (const key of keys) {
const listProp = parent[key];
if (Array.isArray(listProp)) {
Expand All @@ -251,7 +298,7 @@ function sibling(node, selector, ancestry, side) {
upperBound = listProp.length;
}
for (let k = lowerBound; k < upperBound; ++k) {
if (matches(listProp[k], selector, ancestry)) {
if (isNode(listProp[k]) && matches(listProp[k], selector, ancestry, options)) {
return true;
}
}
Expand All @@ -267,21 +314,22 @@ function sibling(node, selector, ancestry, side) {
* @param {SelectorSequenceAST} selector
* @param {external:AST[]} ancestry
* @param {Side} side
* @param {ESQueryOptions|undefined} options
* @returns {boolean}
*/
function adjacent(node, selector, ancestry, side) {
function adjacent(node, selector, ancestry, side, options) {
const [parent] = ancestry;
if (!parent) { return false; }
const keys = estraverse.VisitorKeys[parent.type];
const keys = getVisitorKeys(parent, options);
for (const key of keys) {
const listProp = parent[key];
if (Array.isArray(listProp)) {
const idx = listProp.indexOf(node);
if (idx < 0) { continue; }
if (side === LEFT_SIDE && idx > 0 && matches(listProp[idx - 1], selector, ancestry)) {
if (side === LEFT_SIDE && idx > 0 && isNode(listProp[idx - 1]) && matches(listProp[idx - 1], selector, ancestry, options)) {
return true;
}
if (side === RIGHT_SIDE && idx < listProp.length - 1 && matches(listProp[idx + 1], selector, ancestry)) {
if (side === RIGHT_SIDE && idx < listProp.length - 1 && isNode(listProp[idx + 1]) && matches(listProp[idx + 1], selector, ancestry, options)) {
return true;
}
}
Expand All @@ -301,12 +349,13 @@ function adjacent(node, selector, ancestry, side) {
* @param {external:AST} node
* @param {external:AST[]} ancestry
* @param {IndexFunction} idxFn
* @param {ESQueryOptions|undefined} options
* @returns {boolean}
*/
function nthChild(node, ancestry, idxFn) {
function nthChild(node, ancestry, idxFn, options) {
const [parent] = ancestry;
if (!parent) { return false; }
const keys = estraverse.VisitorKeys[parent.type];
const keys = getVisitorKeys(parent, options);
for (const key of keys) {
const listProp = parent[key];
if (Array.isArray(listProp)) {
Expand Down Expand Up @@ -347,24 +396,25 @@ function subjects(selector, ancestor) {
* @param {external:AST} ast
* @param {?SelectorAST} selector
* @param {TraverseVisitor} visitor
* @param {ESQueryOptions} [options]
* @returns {external:AST[]}
*/
function traverse(ast, selector, visitor) {
function traverse(ast, selector, visitor, options) {
if (!selector) { return; }
const ancestry = [];
const altSubjects = subjects(selector);
estraverse.traverse(ast, {
enter (node, parent) {
if (parent != null) { ancestry.unshift(parent); }
if (matches(node, selector, ancestry)) {
if (matches(node, selector, ancestry, options)) {
if (altSubjects.length) {
for (let i = 0, l = altSubjects.length; i < l; ++i) {
if (matches(node, altSubjects[i], ancestry)) {
if (matches(node, altSubjects[i], ancestry, options)) {
visitor(node, parent, ancestry);
}
for (let k = 0, m = ancestry.length; k < m; ++k) {
const succeedingAncestry = ancestry.slice(k + 1);
if (matches(ancestry[k], altSubjects[i], succeedingAncestry)) {
if (matches(ancestry[k], altSubjects[i], succeedingAncestry, options)) {
visitor(ancestry[k], parent, succeedingAncestry);
}
}
Expand All @@ -375,7 +425,8 @@ function traverse(ast, selector, visitor) {
}
},
leave () { ancestry.shift(); },
fallback: 'iteration'
keys: options && options.visitorKeys,
fallback: options && options.fallback || 'iteration'
});
}

Expand All @@ -385,13 +436,14 @@ function traverse(ast, selector, visitor) {
* match the selector.
* @param {external:AST} ast
* @param {?SelectorAST} selector
* @param {ESQueryOptions} [options]
* @returns {external:AST[]}
*/
function match(ast, selector) {
function match(ast, selector, options) {
const results = [];
traverse(ast, selector, function (node) {
results.push(node);
});
}, options);
return results;
}

Expand All @@ -408,10 +460,11 @@ function parse(selector) {
* Query the code AST using the selector string.
* @param {external:AST} ast
* @param {string} selector
* @param {ESQueryOptions} [options]
* @returns {external:AST[]}
*/
function query(ast, selector) {
return match(ast, parse(selector));
function query(ast, selector, options) {
return match(ast, parse(selector), options);
}

query.parse = parse;
Expand Down
32 changes: 32 additions & 0 deletions tests/fixtures/customNodes.js
View file
@@ -0,0 +1,32 @@
export default {
type: 'CustomRoot',
list: [
{
type: 'CustomChild',
name: 'one',
sublist: [{ type: 'CustomGrandChild' }],
},
{
type: 'CustomChild',
name: 'two',
sublist: [],
},
{
type: 'CustomChild',
name: 'three',
sublist: [
{ type: 'CustomGrandChild' },
{ type: 'CustomGrandChild' },
],
},
{
type: 'CustomChild',
name: 'four',
sublist: [
{ type: 'CustomGrandChild' },
{ type: 'CustomGrandChild' },
{ type: 'CustomGrandChild' },
],
},
],
};

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