Handy methods for manipulating objects, arrays, dates, and strings. I use this primarily to extend Underscore, a library of JavaScript utility methods which I use for most projects.
For the most part, if the method I need is found in Underscore I use that. In some cases I re-wrote the Underscore method to my liking to avoid the dependency of this library on Underscore.
Many of these functions can be found in other libraries, however it can be costly to import an entire library to get access to 1 or 2 functions. In those cases, I elected to write my own and include them here.
Return a list of unique documents by applying the key value of idString provided to each document. If not provided the idString defaults to _id.
uniqueDocs([{_id:"1"}},{_id:"2"},{_id:"1"}]);
// => [{_id:"1"}},{_id:"2"}]
Return a list of unique document ids. The optional idString creates a list of unique values for any property common to all documents. The default value for idString is _id.
getIds([{id:"1"}},{id:"2"},{id:"1"}]);
// => ["1", "2"]
Returns an object hash keyed by the document values of idString. The value of each key is an array of documents. If not provided the idString defaults to _id. Use this to create lookup tables for any document property.
Note: if the idString property is not unique, only the first document containing the property will be indexed.
indexByKey([{_id:"1"}},{_id:"2"},{_id:"1"}]);
// => {1: {_id:"1"}, 2: {_id:"2"}]
Remove documents in list1 that are also found in list2 using the value of idString or _id if not provided.
Use this when you have a manifest list of documents to process (docs1) and a list of already processed docs (docs2).
filterByKey([{_id:"1"}},{_id:"2"}], [{_id:"1")]);
// => [{_id:"2"}]
Returns true if all the members of array list1 are present in array list2. If idString provided then list1 and list2 must be arrays of objects with idString properties for each index of the array.
compare([1, 2, 3],[3, 2, 1, 4]);
// => true
compare([1, 2], [2, 3]);
// => false
compare([{id:"1"}},{id:"2"}], [{id:"2"}},{id:"1"}], 'id');
// => true
Returns true if both arrays have same elements in the same order.
identical([1, 2], [2, 1]);
// => false
Returns all items in list1 also found in list2 to listN.
intersection([1, 2, 3], [2, 1], [1, 2]);
// => [2, 1]
Returns true if all items in list1 also found in list2 to `listN1.
intersects([1, 2, 3], [2, 1], [1, 2]);
// => [2, 1]
Works just like _.extend does shallow copy of all properties in objects to the destination object. Any nested objects or arrays will be copied by reference, not duplicated. It's in-order, so the last source will override properties of the same name in previous arguments.
extend({a: 5}, {b:6});
// => {a:5, b:6}
Removes key/values from obj whose value === undefined, then extends the object with objects provided as arguments.
clean({a: 5, b: undefined});
// => {a: 5}
Returns obj without its prototype properties.
var SomeObject = function() { return this; };
SomeObject.prototype.someKey = 5;
var someObject = new SomeObject();
someObject.myKey = 6;
console.log(someObject.someKey, someObject.myKey);
// => 5, 6
someObject = purify(someObject);
console.log(someObject.someKey, someObject.myKey);
// => undefined, 6
Makes a copy of obj and lower cases all keys and values. Usefull when maninpulating data from unknown sources.
objToLower({Key: 'Some Value'});
// => {key: 'some value'}
Force a value to a known type. baseType is one of number, string, array, or boolean. Usefule when dealing with URL string parameters where values for true and false are always truthy strings 'true' and 'false'.
coerce('number', '5');
// => 5
coerce('string', 5);
// => '5'
coerce('boolean', 'true');
// => true
coerce('string', true);
// => 'true'
Searches an object for the first value of property and returns it.
var obj = {family:{children:{brother: 3, sister: 2}}}
pfetch(obj, 'brother');
// => 3
pfetch(obj, 'children');
// => {brother: 3, sister: 2}
pfetch(obj, 'something');
// => undefined
Like pfetch but property to search is the an array argument, or multiple arguments to the function.
var obj = {family:{children:{brother: 3, sister: 2}}}
fetch(obj, 'mother', 'brother');
// => 3
fetch(obj, ['children', 'sister']);
// => {brother: 3, sister: 2}
Return a hierarchical property value based on the select.string. Usefull when testing existence of a value for a property.
Note: Period '.' or forward slash '/' characters are valid separators.
var obj = {family:{children:{brother: 3, sister: 2}}}
hfetch(obj, 'family.children.brother');
// => 3
hfetch(obj, 'family/children/sister');
// => 2
hfetch(obj, 'family.mother');
// => undefined
Utilities for cleaning strings and calculating similarity.
Returns true if email appears to be a valid email.
validateEmail('[email protected]')
// => true
validateEmail('@example.com')
// => false
Returns true if any characters in string are not alphas or numbers.
hasNonAlphaNumeric('no!');
// => true
hasNonAlphaNumeric('yes');
// => false
Replaces non-alphanumeric characters with an optional substitute string.
filterNonAlphaNumeric('no!', '-');
// => 'no-'
Removes characters with ascii codes that resolve to 0 embedded in the string.
Trims the string and removes ascii codes > 255 embedded in the string.
Formats a number or numeric string.
numberWithCommas( '123456' )
// => '123,456'
Trims a string, remove newlines, carriage returns, embedded parens and braces, punctuation, asterisks from a string.
Removes leading and trailing white space, newlines and carriage returns, and extra embedded white space.
trim('this is a\nstring . ');
// => 'this is a string'
Capitalizes the first character of a string.
initialCapse('welcome home');
// => 'Welcome home
Capitalizes the first character of each word in a string.
allCaps('welcome home');
// => 'Welcome Home'
Returns an integer by calculating the number of changes needed to turn str1 into str2.
editDistance(abc', 'aabddc');
// => 3
Returns a fraction between 0 and 1 to using the editDistance as a percentage of the longer string.
similarity( 'abc', 'aabddc');
// => 0.5
Create a date manipulation object.
Supply date as a number, string, or Date() object. If no date is provided the object will take on today's date.
If you do not supply an optional timeZone the object will take on the time zone of the local machine where executing. You can over-ride the time zone by including it in the date specification by supplying a string, i.e., '2019-07-04 EDT'. Otherwise provide the timeZone to over-ride the default local machine time zone.
Moment provides a powerful and universal date manipulation library. For many projects Moment increases the size of your code quite a bit. Since for many data science projects I standardize on 'YYYY-MM-DD' format for dates I need only a few light-weight methods to calculate and format dates.
Note: Unless otherwise specified, all date values are based on time zone of local machine.
Just like new Date().valueOf()
Returns true if the object is manipulating a valid date.
Returns 4-digit 'YYYY' value.
Returns current year minus num. String or numeric argument is supported.
Defaults to 'YYYY-MM-DD' if no fmt provided. Allows MMM DD YYYY also.
Calculates a new date value based on the supplied num and the period which can be one of: 'year', 'month', 'week', 'day', 'years', 'months', 'weeks', 'days' and modifies the value of the current object.
Calculates the integer difference in milliseconds between dateStr and the value of the current object.
Returns true if the value of the current object equals todays' date.
var myDate = likeMoment( '2019-07-04' );
myDate.today();
// => false
likeMoment( '2019-07-05' ).today();
// => true
likeMoment( '2019-07-05' ).valueOf();
// => 1562299200000
likeMoment( '2019-07-05' ).formatYear();
// => '2019'
likeMoment().recentYear(4);
// => '2015'
likeMoment().format('MMM DD YYYY');
// => 'Jul 05, 2019'
likeMoment().subtract(1, 'year').format();
// => '2018-07-05'
likeMoment( '2019-07-05').subtract(1, 'day').format();
// => '2019-07-04'
likeMoment( '2019-07-05').subtract(1, 'day').format('MMM DD YYYY');
// => 'Jul 04, 2019
likeMoment( '2019-07-05').diff('2019-07-03', 'day');
// => 2
likeMoment().today();
// => true