How to create your own Custom Wordpress Functions.php File

If someone want to create a custom WordPress Theme then functions.php is the most important file. For creating a WordPress Theme, we have to at least some files listed below :

style.css
index.php
functions.php
header.php
footer.php
page.php

Above listed files are minimum requirement for and WordPress Custom Theme. Today I will show how to create a functions.php, how to enqueue Style Sheets(CSS) and JavaScript, adding featured image support, excerpt length change and so on….

Creating functions.php with Bootstrap 4 CDN files, also we will keep CSS and JavaScript file in footer, so as per google content will load first and then others files, it will also add some good reputation on search engine’s eye.

<?php
//loading css files in footer
add_action( 'get_footer', 'load_styles' );
function load_styles() {
wp_enqueue_style( 'style', get_stylesheet_uri(), false );
wp_enqueue_style( 'bootstrap', "https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css", false );
wp_enqueue_style( 'main', get_template_directory_uri()."/css/main.css", false );

}
//loading Js file in footer also
add_action('wp_enqueue_scripts','load_js');
function load_js(){

wp_register_script( 'Jquery','https://code.jquery.com/jquery-3.2.1.slim.min.js','','', true );
wp_register_script( 'Popper','https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js','','', true );
wp_register_script( 'Bootstrap', 'https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js','','', true );
wp_register_script( 'Main', get_template_directory_uri()."/js/main.js",'','', true );

wp_enqueue_script( 'Jquery' );
wp_enqueue_script( 'Popper' );
wp_enqueue_script( 'Bootstrap' );
wp_enqueue_script( 'Main' );

}
//Feature image
add_theme_support( 'post-thumbnails' );
//creating thumbnail footer-thumb size 64X64
add_image_size( 'footer-thumb', 64, 64, false );
//creating thumbnail thumb128 size 128X128
add_image_size( 'thumb128', 128, 128, false );
//Custom length excerpt
function custom_excerpt_length( $length ) {
return 40;//set custom value instead of 40
}
function new_excerpt_more($more) {
global $post;
}
add_filter('excerpt_more', 'new_excerpt_more');
add_filter( 'excerpt_length', 'custom_excerpt_length', 999 );

// Site Logo using Cutomizer
add_action( 'customize_register', 'sp_customize_register' );
function sp_customize_register( $wp_customize ) {

$wp_customize->add_section( 'sp_logo' , array(
'title' => __( 'Site Logo', 'sp' ),
'description' => 'Modify the site logo image'
));
$wp_customize->add_setting( 'site_logo' , array(
'default' => ''
));
$wp_customize->add_control( new WP_Customize_Image_Control(
$wp_customize,
'site_logo',
array(
'label' => __( 'Upload Site Logo', 'sp' ),
'section' => 'sp_logo',
'settings' => 'site_logo'
)
));
}
?>