how to use the topath function from the lodash library in typescript

To use the topath function from the lodash library in TypeScript, first, you need to install lodash by running the following command in your terminal:

index.ts
npm install lodash
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Then, you need to import the topath function from lodash in your TypeScript file:

index.ts
import { topath } from 'lodash';
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The topath function takes a string or an array of strings, and returns an array of strings, which represents the path to the input property. For example:

index.ts
const input = { a: { b: { c: 1 } } };
const path = topath('a.b.c');
const value = _.get(input, path);

console.log(value); // Output: 1
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In this example, topath is used to convert the property path string 'a.b.c' into an array of strings ['a', 'b', 'c'], which represents the path to the property c of the object input. Then, the _.get function from lodash is used to get the value of the property c from the object input, by passing the object and the path array as arguments. The output is 1, which is the value of the property c.

You can also use generics to infer the type of the input object and the type of the output value, as follows:

index.ts
function getValue<T, R>(input: T, path: string): R | undefined {
  const pathArray = topath(path);
  return _.get(input, pathArray) as R | undefined;
}

const input = { a: { b: { c: 1 } } };
const value = getValue<typeof input, number>(input, 'a.b.c');

console.log(value); // Output: 1
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In this example, the getValue function takes two generic type parameters T and R, which represent the type of the input object and the type of the output value, respectively. The function uses the topath function to convert the property path string into an array of strings, and then uses the _.get function to get the value of the property from the input object, by passing the object and the path array as arguments. The output type is inferred from the generic type parameter R.