如何过滤对象数组并检查数组内是否有多个 object 在 Javascript 中具有相同的属性值？

Question

如何过滤对象数组并检查数组中是否有多个 object 在 Javascript 中具有相同的属性值计划“企业”。

    this.accounts
              .filter(
                item => item.plan === 'enterprise'
              )
              // then how can I check if there is more than one object
              // containing above enterprise value? if so then return some message.
          }

如何继续进行上述过滤以达到结果？

Answer 1

您可以获取数组的长度，然后检查它是否大于一，因此打印一条消息

 const elmCount = this.accounts
   .filter(
     item => item.plan === 'enterprise'
   ).length

 if (elmCount > 1) {
   console.log('print message')
 }

Answer 2

执行过滤器后，您可以只计算filter方法结果中的项目数。 这将告诉您有多少个企业计划帐户

 var accounts = [ {id: 1, name: "Account 1", plan: "basic"}, {id: 2, name: "Account 2", plan: "medium"}, {id: 3, name: "Account 3", plan: "enterprise"}, {id: 4, name: "Account 4", plan: "medium"}, {id: 5, name: "Account 5", plan: "enterprise"} ] var enterpriseAccounts = accounts.filter(item => item.plan === "enterprise"); if(enterpriseAccounts.length > 1 ) { console.log('There are more than one enterprise account'); } else { console.log('There are 0 or 1 enterprise account'); }

Answer 3

只需过滤然后获取长度。

 accounts = [{plan: 'test'}, {plan: 'extra'}, {plan: 'enterprise'}, {plan: 'basic'}, {plan: 'enterprise'}]; let length = accounts.filter(item => item.plan === 'enterprise').length; if (length>1) console.log('enterprise more than once: ' + length);