Angular2 string capitalisation pipe

capitalize.pipe.ts

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({ 
    name: 'capitalize' 
})
export class Capitalize implements PipeTransform {
    
    transform(str: string, all: boolean) {
        //Capitalize all the words
        if (all) {
            return str.split(' ').map((str) => {
                return str.charAt(0).toUpperCase() + str.slice(1);
            }).join(' ');
        }
        //Capitalize the first word only
        return str.charAt(0).toUpperCase() + str.slice(1); 
    }
    
}

hello.component.ts

import { Component } from '@angular/core';
import { Capitalize } from './capitalize.pipe';

@Component({
    template: `
        <h1>{{ title | capitalize:true }}</h1>
        <h2>{{ subTitle }}</h2>
    `,
    pipes: [Capitalize]
})
export class HelloComponent {

    title = 'hello world title';
    subTitle = 'hello world sub title';
    
    constructor() {
        this.subTitle = new Capitalize().transform(this.subTitle, true);
    }

}