假資料結構產生器

• 假資料結構產生器
  • 用途
    • createValueGenerator
    • createSelectionGenerator
    • createObjectGenerator
    • createArrayGenerator
    • createTupleGenerator
    • createBoundedSeriesGenerator
  • 擴充

用途

使用 faker js 時是單一純值不能產生結構，需要自己手動組合結構，此專案利用撰寫設定檔的方式來產生一個特定的假資料函數，減少手動組合結構的麻煩。

const test = {
  type: 'obj',
  content: {
    name: {
      type: 'value',
      generateFn: () => 'hello',
    },
    list: {
      type: 'arr',
      len: 5,
      item: {
        type: 'value',
        generateFn: () => 10,
      },
    },
  },
};

const generateFn = createGeneratorByType(test);

console.log(generateFn());

/*
{
  name: "hello"
  list: [10, 10, 10, 10, 10,]
}
*/

createValueGenerator

const generateFn = createValueGenerator({
  type: 'value',
  generateFn: () => 10,
})

console.log(generateFn());

// 10

createSelectionGenerator

const generateFn = createSelectionGenerator({
 type: 'select',
 items: [1, 2, 3, 4, 5],
})

console.log(generateFn());

// 1 or 2 or 3 or 4 or 5

createObjectGenerator

const generateFn = createObjectGenerator({
 type: 'obj',
 content: {
   name: {
     type: 'value',
     generateFn: () => 'hello',
   },
   list: {
     type: 'arr',
     len: 5,
     item: {
       type: 'value',
       generateFn: () => 10,
     }
   }
 }
})

console.log(generateFn());

// {
//   name: 'hello',
//   list: [10, 10, 10, 10, 10]
// }

createArrayGenerator

const generateFn = createArrayGenerator({
 type: 'arr',
 len: 5,
 item: {
   type: 'value',
   generateFn: () => 10,
 }
})

console.log(generateFn());

// [10, 10, 10, 10, 10]

createTupleGenerator

const generateFn = createTupleGenerator({
 type: 'tuple',
 configItems: [
   {
     type: 'value',
     generateFn: () => 10,
   },
   {
     type: 'value',
     generateFn: () => 'hello',
   },
 ]
})

console.log(generateFn());

// [10, 'hello']

createBoundedSeriesGenerator

const generateFn = createBoundedSeriesGenerator({
 type: 'bounded_series',
 upperLimit: 1.1,
 lowerLimit: 0.9,
 createInitValue: () => 100,
 count: 20
})

console.log(generateFn());

// [100 * 0.9 <= num <= 100 * 1.1, 
//  prev * 0.9 <= num <= prev * 1.1,
//  prev * 0.9 <= num <= prev * 1.1,
//  ...] 

擴充

一切的值皆由 value 產生，可以自己創建各種不同亂數函數

flowchart TB
 value --> int
 value --> float
 value --> string
 value --> email
 value --> other[...]

但並不是所有人情況都能自己手動建立函數，有可能是開放給別人使用的服務，沒辦法在使用方建立函數，這時 createGeneratorByType 第二個可以讓製作服務的人帶入自己的擴充，這樣這個函數就能接受更多種型態。

const createIntValueConfig = (option) => createValueConfig(() => faker.number.int(option));
const createEmailValueConfig = (option) => createValueConfig(() => faker.internet.email(option));

const customTypeMatch = (config) => {
  if (config.type === "int") {
    return createIntValueConfig(config.option);
  }
  if (config.type === "email") {
    return createEmailValueConfig(config.option);
  }

  throw Error("error");
};

const config = {
  type: "obj",
  content: {
    name: { type: "value", generateFn: () => "John" },
    age: { type: "int" },
    email: { type: "email" },
  },
};

const result = createGeneratorByType(config, customTypeMatch)();

console.log(result);

/*
  {
    name: "John",
    age: 50,
    email: "[email protected]",
  }
*/