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26 lines
876 B
26 lines
876 B
/**
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* Utility functions that need to be reimplemented for each environment.
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* This is the version for Node.js
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* @module customUtilsNode
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* @private
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*/
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const crypto = require('crypto')
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/**
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* Return a random alphanumerical string of length len
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* There is a very small probability (less than 1/1,000,000) for the length to be less than len
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* (il the base64 conversion yields too many pluses and slashes) but
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* that's not an issue here
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* The probability of a collision is extremely small (need 3*10^12 documents to have one chance in a million of a collision)
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* See http://en.wikipedia.org/wiki/Birthday_problem
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* @param {number} len
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* @return {string}
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* @alias module:customUtilsNode.uid
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*/
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const uid = len => crypto.randomBytes(Math.ceil(Math.max(8, len * 2)))
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.toString('base64')
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.replace(/[+/]/g, '')
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.slice(0, len)
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// Interface
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module.exports.uid = uid
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