Jel.String

Trim, extract, and compare strings
Language-Specific functions

Trimming and substring functions

Trimming white-space from strings is made simple with using the rtrim, ltrim, and trim functions inside Jel.String:

Jel.String.ltrim(" blah "); // "blah "; Jel.String.rtrim(" blah "); // " blah"; Jel.String.trim(" blah "); // "blah";

While JavaScript has two functions to extract substrings (substr, and substring), it doesn't have any convenient ways to get a certain number of characters from the left or right of a string. Jel makes this easy:

Jel.String.left("workplace", 4); // "work" Jel.String.right("workplace", 5); // "place"

And that about covers that really. Simple but useful functions, that are strangely absent from the core of many languages.

Comparison functions

Jel.String has a number of similarly useful and easy to understand comparison functions: equals, startsWith, and endsWith. These functions have the extra benefit of being able to ignore case too:

Jel.String.equals("jel", "JEL", true); // true (ignoreCase is true) Jel.String.endsWith("word", "ord"); // true Jel.String.endsWith("word", "ORD", true); // true (ignoreCase is true) Jel.String.endsWith("word", "e"); // false Jel.String.startsWith("field-container", "field"); // true

Converting between variable naming standards

Naming standards for XHTML class and id attributes can vary a lot between developers and teams. When delimiting separate words in a class or id string, there common standards to adhere to are:

• camel case - the first word is lower case, with additional words having their first letter as uppercase - e.g. camelCase, containerField
• dash delimited - all letters are lower case, with each word being separated by a dash - e.g. dash-delimited, container-field
• underscore delimited - all letters are lower case, with each word being separated by an underscore - e.g. underscore_delimited, container_field

To convert between these naming standards, Jel.String has the functions normalize, camelize, and decamelize. normalize acts as a bridge between these naming standards, by converting any of the above naming standards, or even a mixture of them in one string, into the dash delimited version:

alert(Jel.String.normalize("flowerPower")); // flower-power alert(Jel.String.normalize("flower_power")); // flower-power alert(Jel.String.normalize("flower-power")); // flower-power alert(Jel.String.normalize("flower-powerAmazing_stuff")); // flower-power-amazing-stuff

Once you have a normlized string, it's trivial to convert into any of the other standards:

var str = Jel.String.normalize("fieldContainer"); // would probably not be a constant string parameter in reality alert(Jel.String.camelize(str)); // fieldContainer alert(str.replace("-", "_"); // field_container

Finally, decamelize does the opposite of camelize, breaking up a camel case word into delimited words with a delimiter of your choice (default dash "-"):

var str = Jel.String.decamelize("fieldContainer"); // "field-container"

Integer extraction

The built-in JavaScript function parseInt is a handy function at times, but not so good when you know a number exists somewhere in the middle or end of a string. In those cases parseInt returns "NaN", as shown below:

parseInt("33times"); // 33 parseInt("times33"); // NaN

The Jel.String.extractInt function is designed to solve this problem, and can even return the resulting integer if numbers are not contiguous in the string:

Jel.String.extractInt("one2three"); // 2 Jel.String.extractInt("one24t3"); // 243 Jel.String.extractInt("item-12"); // 12

Language Specific Functions

The English-language builds of JEL contain a few extra nuggets in Jel.String for constructing sentences: an and plural.

var test1 = "apple"; var test2 = "fly"; // plural takes a count as its second param Jel.String.plural(test1, 1); // "apple" Jel.String.plural(test1, 2); // "apples" Jel.String.an(test1) + test1; // "an apple" Jel.String.plural(test2, 1); // "fly" Jel.String.plural(test2, 2); // "flies" Jel.String.an(test1) + test1; // "a fly"

More information

All functions discussed here (and a few more) are detailed in the API documentation for Jel.String.

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