Rxjs之创建操作符（Angular环境）

一 of操作符

import { Component, OnInit } from '@angular/core';
import { of } from 'rxjs/observable/of';
import { Observable } from 'rxjs/Observable';
 
@Component({
  selector: 'app-create',
  templateUrl: './create.component.html',
  styleUrls: ['./create.component.css']
})
export class CreateComponent implements OnInit {
 
  constructor() { }
 
  ngOnInit() {
 
    // 从数组创建
 
    const arr = ['red', 'yellow', 'blue'];
    const colors: Observable<string[]> = of(arr);
    colors.subscribe((colorsArr: string[]) => {
      console.log(colorsArr);
    });
 
    // 从迭代器对象创建
 
    const map: Map<string, any> = new Map();
    map.set('fruit', 'orange');
    of(map).subscribe(
      (fruitsMap: Map<string, any>) => {
        console.log(fruitsMap);
      }
    );
  }
 
}

二 from操作符

import { Component, OnInit } from '@angular/core';
import { from } from 'rxjs/observable/from';
import { Observable } from 'rxjs/Observable';
 
@Component({
  selector: 'app-create',
  templateUrl: './create.component.html',
  styleUrls: ['./create.component.css']
})
export class CreateComponent implements OnInit {
 
  constructor() { }
 
  ngOnInit() {
 
    // 从数组创建
 
    const arr = ['red', 'yellow', 'blue'];
    const colors: Observable<string> = from(arr);
    colors.subscribe((color: string) => {
      console.log(color);
    });
 
  }
 
}

三 interval操作符

返回从0开始的无限自增整数序列，每个固定的时间间隔发送。第一次并 没有立马去发送, 而是第一个时间段过后才发出。

import { Component, OnInit } from '@angular/core';
import { interval } from 'rxjs/observable/interval';
import { Observable } from 'rxjs/Observable';
 
@Component({
  selector: 'app-create',
  templateUrl: './create.component.html',
  styleUrls: ['./create.component.css']
})
export class CreateComponent implements OnInit {
 
  constructor() { }
 
  ngOnInit() {
 
    interval(1000).subscribe((val: number) => {
      console.log(val);
    });
 
  }
 
}

四 range操作符

range 操作符顺序发出一个区间范围内的连续整数, 你可以决定区间的开始和长度。

import { Component, OnInit } from '@angular/core';
import { range } from 'rxjs/observable/range';
import { Observable } from 'rxjs/Observable';
 
@Component({
  selector: 'app-create',
  templateUrl: './create.component.html',
  styleUrls: ['./create.component.css']
})
export class CreateComponent implements OnInit {
 
  constructor() { }
 
  ngOnInit() {
 
    range(600, 10).subscribe((val: number) => {
      console.log(val);
    });
 
  }
 
}