Mapping the object keys with regexp with javascript

Question

An array of objects contains a key "dataTypes" with many data types fetched from the backend . All these dataTypes should be categorized into four segments number, string, date, boolean . Since there are many dataTypes I am figuring out having an object mapping with key allows regexp .

const data = [
        {
            "title": "id",
            "dataTypes": "character varying(65535)"
        },
        {
            "title": "value",
            "dataTypes": "int"
        },
        {
            "title": "number_value",
            "dataTypes": "bigint"
        },
        {
            "title": "first_name",
            "dataTypes": "varchar"
        },
        {
            "title": "last_name",
            "dataTypes": "char"
        },
        {
            "title": "activated_date",
            "dataTypes": "date without timestamp"
        },
        {
            "title": "selected",
            "dataTypes": "boolean"
        },
]
const objectMap = {
  "char" : "string",
  "varchar" : "string",
  "character varying(65535)" : "string",
  "int" : "number",
  "numeric" : "number",
  "bigint" : "number",
  "boolean" : "boolean",
  "date" : "date",
  "date without timestamp" : "date"
};
data.map(el => el.dataTypes = objectMap[el.dataTypes])
console.log(data)

since I need to add more keys in the object, is there anyway I could use regexp as keys

const objectMap = {
   .*char.* : "string"
}

Expected result :

const data = [
        {
            "title": "id",
            "dataTypes": "string"
        },
        {
            "title": "value",
            "dataTypes": "int"
        },
        {
            "title": "number_value",
            "dataTypes": "int"
        },
        {
            "title": "first_name",
            "dataTypes": "string"
        },
        {
            "title": "last_name",
            "dataTypes": "string"
        },
        {
            "title": "activated_date",
            "dataTypes": "date"
        },
        {
            "title": "selected",
            "dataTypes": "boolean"
        },
]

Andreas · Accepted Answer · 2019-09-06 15:10:57Z

1

You can use another array with all the possible replacement values and a matching criteria - which can then be a string or a regular expression (or a function or ...)

const data = [
  { "title": "id", "dataTypes": "character varying(65535)" },
  { "title": "value", "dataTypes": "int" },
  { "title": "number_value", "dataTypes": "bigint" },
  { "title": "first_name", "dataTypes": "varchar" },
  { "title": "last_name", "dataTypes": "char" },
  { "title": "activated_date", "dataTypes": "date without timestamp" },
  { "title": "selected", "dataTypes": "boolean" },
];

const replacements = [
  { criteria: /.*char.*/, replacement: "string" },
  { criteria: "int", replacement: "number" },
  { criteria: "numeric", replacement: "number" },
  { criteria: "bigint", replacement: "number" },
  { criteria: "boolean", replacement: "boolean" },
  { criteria: /date.*/, replacement: "date" }
];

data.forEach(d => {
  const needle = replacements.find(r => {
    if (typeof r.criteria === "string") {
      return d.dataTypes === r.criteria;
    } else {
      return r.criteria.test(d.dataTypes);
    }
  });

  d.oldDataTypes = d.dataTypes;  // only for easier validation in the console
  d.dataTypes = needle ? needle.replacement : d.dataTypes;
})

console.log(data);

answered Sep 6, 2019 at 15:10

Andreas

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1 Comment

RenJith Over a year ago

great solution ! But it takes some time to compute

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