39 lines
926 B
JavaScript
39 lines
926 B
JavaScript
'use strict';
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/**
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* Convert a string or array into a projection object. Treats `-foo` as
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* equivalent to `foo: 0` depending on `retainMinusPaths`. If `retainMinusPaths`
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* is true, then `-foo` will be included in the projection as `'-foo': 0`.
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*
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* @param {object|string|string[]} v
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* @param {boolean} [retainMinusPaths]
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* @return {object}
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*/
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module.exports = function parseProjection(v, retainMinusPaths) {
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const type = typeof v;
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if (type === 'string') {
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v = v.split(/\s+/);
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}
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if (!Array.isArray(v) && Object.prototype.toString.call(v) !== '[object Arguments]') {
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return v;
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}
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const len = v.length;
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const ret = {};
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for (let i = 0; i < len; ++i) {
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let field = v[i];
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if (!field) {
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continue;
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}
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const include = field.charAt(0) === '-' ? 0 : 1;
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if (!retainMinusPaths && include === 0) {
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field = field.slice(1);
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}
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ret[field] = include;
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}
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return ret;
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};
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