Filters
TemplateDX provides a set of built-in filters that you can use to manipulate and transform data within your templates. Filters are functions that take an input value and return a transformed output.
Creating Custom Filters
To create a custom filter in TemplateDX, define a filter function, register it, and apply it in your templates. For example, to create a reverse filter:
reverse("Hello, TemplateDX!")
import { FilterRegistry } from "@puzzlet/templatedx";
export const reverse = (input: string): string => {
if (typeof input !== "string") return input;
return input.split('').reverse().join('');
};
FilterRegistry.register("reverse", reverse);
Built-in Filters
abs
The abs filter returns the absolute value of a number.
Syntax
abs(number_value)
Parameters
number_value(number): The input number.
Example
abs(-42)
Output:
42
Source Code
export const abs = (input: number): number => {
return Math.abs(input);
};
capitalize
The capitalize filter capitalizes the first character of a string.
Parameters
capitalize(string_value)
Parameters
string_value(string): The input string to be capitalized.
Parameters
capitalize("hello world")
Output:
Hello world
Parameters
export const capitalize = (input: string): string => {
if (typeof input !== "string") return input;
return input.charAt(0).toUpperCase() + input.slice(1);
};
dump
The dump filter serializes a JavaScript object into a JSON string.
Syntax
dump(object_value)
Parameters
object_value(any): The input object to be serialized.
Example
dump({ name: "TemplateDX", version: "1.0" })
Output:
{"name":"TemplateDX","version":"1.0"}
Source Code
export const dump = (input: any): string => {
return JSON.stringify(input);
};
join
The join filter joins elements of an array into a single string, separated by a specified separator.
Syntax
join(array_value, separator)
Parameters
array_value(any[]): The input array.separator(string, optional): The string to separate the array elements. Defaults to", ".
Example
join(["apple", "banana", "cherry"], ", ")
Output:
apple, banana, cherry
Source Code
export const join = (input: any[], separator: string = ", "): string => {
if (!Array.isArray(input)) return input;
return input.join(separator);
};
lower
The lower filter converts a string to lowercase letters.
Syntax
lower(string_value)
Parameters
string_value(string): The input string to be converted to lowercase.
Example
lower("HELLO WORLD")
Output:
hello world
Source Code
export const lower = (input: string): string => {
if (typeof input !== "string") return input;
return input.toLowerCase();
};
replace
The replace filter replaces all occurrences of a specified substring with a new substring.
Syntax
replace(string_value, search, replace)
Parameters
string_value(string): The input string.search(string): The substring to search for.replace(string): The substring to replace with.
Example
replace("Hello World", "World", "TemplateDX")
Output:
Hello TemplateDX
Source Code
export const replace = (input: string, search: string, replace: string): string => {
if (typeof input !== "string") return input;
return input.split(search).join(replace);
};
round
The round filter rounds a number to a specified number of decimal places.
Syntax
round(number_value, decimals)
Parameters
number_value(number): The input number to be rounded.decimals(number, optional): The number of decimal places to round to. Defaults to0.
Example
round(3.14159, 2)
Output:
3.14
Source Code
export const round = (input: number, decimals: number = 0): number => {
return Number(Math.round(Number(input + "e" + decimals)) + "e-" + decimals);
};
truncate
The truncate filter truncates a string to a specified length and appends an ellipsis (...) if necessary.
Syntax
truncate(string_value, length)
Parameters
string_value(string): The input string to be truncated.length(number): The maximum length of the output string.
Example
truncate("The quick brown fox jumps over the lazy dog", 20)
Output:
The quick brown fo...
Source Code
export const truncate = (input: string, length: number): string => {
if (typeof input !== "string") return input;
if (input.length <= length) return input;
return input.substring(0, length) + "...";
};
upper
The upper filter converts a string to uppercase letters.
Syntax
upper(string_value)
Parameters
string_value(string): The input string to be converted to uppercase.
Example
upper("hello world")
Output:
HELLO WORLD
Source Code
export const upper = (input: string): string => {
if (typeof input !== "string") return input;
return input.toUpperCase();
};
urlencode
The urlencode filter encodes a string to be safe for use in URLs.
Syntax
urlencode(string_value)
Parameters
string_value(string): The input string to be URL-encoded.
Example
urlencode("Hello World!")
Output:
Hello%20World%21
Source Code
export const urlencode = (input: string): string => {
if (typeof input !== "string") return input;
return encodeURIComponent(input);
};