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51 lines
1.1 KiB
Text
51 lines
1.1 KiB
Text
export function walk(ast, { enter, leave }) {
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visit(ast, null, enter, leave);
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}
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let shouldSkip = false;
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const context = { skip: () => shouldSkip = true };
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export const childKeys = {};
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const toString = Object.prototype.toString;
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function isArray(thing) {
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return toString.call(thing) === '[object Array]';
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}
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function visit(node, parent, enter, leave, prop, index) {
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if (!node) return;
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if (enter) {
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const _shouldSkip = shouldSkip;
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shouldSkip = false;
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enter.call(context, node, parent, prop, index);
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const skipped = shouldSkip;
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shouldSkip = _shouldSkip;
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if (skipped) return;
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}
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const keys = node.type && childKeys[node.type] || (
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childKeys[node.type] = Object.keys(node).filter(key => typeof node[key] === 'object')
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);
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for (let i = 0; i < keys.length; i += 1) {
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const key = keys[i];
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const value = node[key];
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if (isArray(value)) {
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for (let j = 0; j < value.length; j += 1) {
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value[j] && value[j].type && visit(value[j], node, enter, leave, key, j);
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}
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}
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else if (value && value.type) {
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visit(value, node, enter, leave, key, null);
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}
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}
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if (leave) {
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leave(node, parent, prop, index);
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}
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}
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