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node-spearhead/lib/common.js

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/**
* Copyright (c) 2015 Joyent Inc. All rights reserved.
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*/
var assert = require('assert-plus');
var util = require('util'),
format = util.format;
var errors = require('./errors'),
InternalError = errors.InternalError;
// ---- globals
var p = console.log;
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var UUID_RE = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/;
// ---- support stuff
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function objCopy(obj, target) {
if (target === undefined) {
target = {};
}
Object.keys(obj).forEach(function (k) {
target[k] = obj[k];
});
return target;
}
function deepObjCopy(obj) {
return JSON.parse(JSON.stringify(obj));
}
function zeroPad(n, width) {
var s = String(n);
while (s.length < width) {
s = '0' + s;
}
return s;
}
/**
* Convert a boolean or string representation into a boolean, or
* raise TypeError trying.
*
* @param value {Boolean|String} The input value to convert.
* @param default_ {Boolean} The default value is `value` is undefined.
* @param errName {String} The variable name to quote in the possibly
* raised TypeError.
*/
function boolFromString(value, default_, errName) {
if (value === undefined) {
return default_;
} else if (value === 'false' || value === '0') {
return false;
} else if (value === 'true' || value === '1') {
return true;
} else if (typeof (value) === 'boolean') {
return value;
} else {
throw new TypeError(
format('invalid value for "%s": %j', errName, value));
}
}
/**
* given an array return a string with each element
* JSON-stringifed separated by newlines
*/
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function jsonStream(arr, stream) {
stream = stream || process.stdout;
arr.forEach(function (elem) {
stream.write(JSON.stringify(elem) + '\n');
});
}
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/**
* given an array of key=value pairs, break them into an object
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*
* @param {Array} kvs - an array of key=value pairs
* @param {Array} valid (optional) - an array to validate pairs
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*/
function kvToObj(kvs, valid) {
var o = {};
for (var i = 0; i < kvs.length; i++) {
var kv = kvs[i];
var idx = kv.indexOf('=');
if (idx === -1)
throw new errors.UsageError(format(
'invalid filter: "%s" (must be of the form "field=value")',
kv));
var k = kv.slice(0, idx);
var v = kv.slice(idx + 1);
if (valid.indexOf(k) === -1)
throw new errors.UsageError(format(
'invalid filter name: "%s" (must be one of "%s")',
k, valid.join('", "')));
o[k] = v;
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}
return o;
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}
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/**
* return how long ago something happened
*
* @param {Date} when - a date object in the past
* @param {Date} now (optional) - a date object to compare to
* @return {String} - printable string
*/
function longAgo(when, now) {
now = now || new Date();
var seconds = Math.round((now - when) / 1000);
var times = [
seconds / 60 / 60 / 24 / 365, // years
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seconds / 60 / 60 / 24 / 7, // weeks
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seconds / 60 / 60 / 24, // days
seconds / 60 / 60, // hours
seconds / 60, // minutes
seconds // seconds
];
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var names = ['y', 'w', 'd', 'h', 'm', 's'];
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for (var i = 0; i < names.length; i++) {
var time = Math.floor(times[i]);
if (time > 0)
return util.format('%d%s', time, names[i]);
}
return '0s';
}
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/**
* checks a string and returns a boolean based on if it
* is a UUID or not
*/
function isUUID(s) {
return /^([a-f\d]{8}(-[a-f\d]{4}){3}-[a-f\d]{12}?)$/i.test(s);
}
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function humanDurationFromMs(ms) {
assert.number(ms, 'ms');
var sizes = [
['ms', 1000, 's'],
['s', 60, 'm'],
['m', 60, 'h'],
['h', 24, 'd']
];
if (ms === 0) {
return '0ms';
}
var bits = [];
var n = ms;
for (var i = 0; i < sizes.length; i++) {
var size = sizes[i];
var remainder = n % size[1];
if (remainder === 0) {
bits.unshift('');
} else {
bits.unshift(format('%d%s', remainder, size[0]));
}
n = Math.floor(n / size[1]);
if (n === 0) {
break;
} else if (size[2] === 'd') {
bits.unshift(format('%d%s', n, size[2]));
break;
}
}
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if (bits.length > 1 && bits[bits.length - 1].slice(-2) === 'ms') {
bits.pop();
}
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return bits.slice(0, 2).join('');
}
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/**
* Adapted from <http://stackoverflow.com/a/18650828>
*/
function humanSizeFromBytes(bytes) {
assert.number(bytes, 'bytes');
var sizes = ['B', 'KiB', 'MiB', 'GiB', 'TiB'];
if (bytes === 0) {
return '0 B';
}
var i = Number(Math.floor(Math.log(bytes) / Math.log(1024)));
var s = String(bytes / Math.pow(1024, i));
var precision1 = (s.indexOf('.') === -1
? s + '.0' : s.slice(0, s.indexOf('.') + 2));
return format('%s %s', precision1, sizes[i]);
}
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function capitalize(s) {
return s[0].toUpperCase() + s.substr(1);
}
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//---- exports
module.exports = {
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UUID_RE: UUID_RE,
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objCopy: objCopy,
deepObjCopy: deepObjCopy,
zeroPad: zeroPad,
boolFromString: boolFromString,
jsonStream: jsonStream,
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kvToObj: kvToObj,
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longAgo: longAgo,
isUUID: isUUID,
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humanDurationFromMs: humanDurationFromMs,
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humanSizeFromBytes: humanSizeFromBytes,
capitalize: capitalize
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};
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