fix(prop): fix prop.export can not correctly export undefined[]

[liujuping]

该 PR，为了解决 loopArgs不返回[undefined, undefined]，但是会导致需要设置 prop value 为 undefined[] 类型的设置器，无法获取正确的值。

https://github.com/alibaba/lowcode-engine/pull/141/files

Closes #1891

[github-actions]

ChatGPT Code Review:

CodeReview：

根据 diff，代码移除了一个 if 需要关注下这个分支的逻辑，这段逻辑的主要目的是判断是否所有的 items 的值都是 undefined，如果是，则返回 undefined。

如果把 map 的返回值直接返回，是合法的逻辑，因为如果没有 items，子项没有被添加，值就直接返回 value 的内容。但如果 map 的结果中只有 undefined，此时需要根据 if 的逻辑进行返回。

修改建议：

1. 做到 if 的分支目的在代码上也有体现

export class Prop implements IProp, IPropParent {
  // ......
  getValue(stage?: PropExportStage) {
    if (!this._items) {
      return this._value;
    }

    const values = this.items!.map((prop) => {
      return prop?.export(stage);
    });

    const everyValueAreUndefined = values.every((val) => val === undefined)
    if (everyValueAreUndefined) {
      return undefined;
    } else {
      return values;
    }
  }
}

2. 尽可能使用 typeof 和 strict comparison 来做，以避免因为类型不同的隐式转换引入的错误

export class Prop implements IProp, IPropParent {
  // ...
  getValue(stage?: PropExportStage) {
    if (!this._items) {
      return this._value;
    }

    const values = this.items!.map((prop) => {
      return prop?.export(stage);
    });

    if (typeof values[0] === 'undefined' &&
      values.every((value) => value === values[0])) {
      return undefined;
    } else {
      return values;
    }
  }
}

Commit Message：fix(Prop): fix Prop.getValue can not correctly export undefined values。根据 Angular 规范，CommitMessage 包含以下三个部分：

• 类型: fix
• 文件路径: Prop
• 简要说明: fix Prop.getValue can not correctly export undefined values

[github-actions]

Coverage report for packages/utils

St.❔	Category	Percentage	Covered / Total
🔴	Statements	48.18%	119/247
🔴	Branches	42.64%	113/265
🔴	Functions	41.03%	32/78
🔴	Lines	49.36%	115/233

Test suite run success

32 tests passing in 5 suites.

Report generated by 🧪jest coverage report action from f51c700

[github-actions]

Coverage report for packages/renderer-core

St.❔	Category	Percentage	Covered / Total
🟡	Statements	71.95%	908/1262
🟡	Branches	61.23%	567/926
🟡	Functions	69.12%	197/285
🟡	Lines	71.94%	892/1240

Test suite run success

91 tests passing in 8 suites.

Report generated by 🧪jest coverage report action from f51c700

[github-actions]

Coverage report for packages/react-simulator-renderer

St.❔	Category	Percentage	Covered / Total
🔴	Statements	33.63%	114/339
🔴	Branches	14.88%	25/168
🔴	Functions	26.14%	23/88
🔴	Lines	34.23%	114/333

Test suite run success

2 tests passing in 1 suite.

Report generated by 🧪jest coverage report action from f51c700

[github-actions]

Coverage report for packages/designer

St.❔	Category	Percentage	Covered / Total
🟢	Statements	96.34% (-0% 🔻)	2842/2950
🟢	Branches	88.83% (-0.01% 🔻)	1630/1835
🟢	Functions	95.97% (-0% 🔻)	858/894
🟢	Lines	96.41% (-0% 🔻)	2769/2872

Show files with reduced coverage 🔻

St.❔	File	Statements	Branches	Functions	Lines
🟢	... / prop.ts	99.32% (-0.01% 🔻)	92.19% (-0.06% 🔻)	100%	99.31% (-0.01% 🔻)

Test suite run success

370 tests passing in 42 suites.

Report generated by 🧪jest coverage report action from f51c700