align-arr
Find the minimal edit path between two generic arrays.
Installation
npm i align-arr
or
yarn add align-arr
Usage
Find the difference between two arrays of number.
import { align } from 'align-arr';
const source = [1, 3, 3];
const target = [1, 2, 3];
const alignment: Edit<number>[] = align(source, target);
console.log(alignment);
[
{
operation: 'equal',
source: { position: 0, data: 1 },
target: { position: 0, data: 1 },
cost: 0
},
{
operation: 'substitute',
source: { position: 1, data: 3 },
target: { position: 1, data: 2 },
cost: 1
},
{
operation: 'equal',
source: { position: 2, data: 3 },
target: { position: 2, data: 3 },
cost: 0
}
]
The console logs an array of Edit objects describing the difference between source and target.
export type Edit<S = any, T = S> = {
operation: Operation;
source: Chunk<S>;
target: Chunk<T>;
cost: number;
};
export type Operation = 'equal' | 'insert' | 'delete' | 'substitute';
export type Chunk<T = any> = {
position: number;
data?: T;
};
Customizing The Aligner
By default, the algorithm compares two elements as a === b, and has a fixed cost of 1 for each operation.
In this example, we override the equals method to compare between a number and a string, and assign a fixed cost of 10 to the substitute operation, which causes the algorithm to favour insert and delete instead.
const source = [1, 3, 3];
const target = ['1', '2', '3'];
const alignment = align(source, target, {
equals: (a, b) => a === Number.parseFloat(b),
insCost: (a) => 1,
delCost: (a) => 1,
subCost: (a, b) => 10,
});
console.log(alignment);
[
{
operation: 'equal',
source: { position: 0, data: 1 },
target: { position: 0, data: '1' },
cost: 0
},
{
operation: 'insert',
source: { position: 1, data: undefined },
target: { position: 1, data: '2' },
cost: 1
},
{
operation: 'delete',
source: { position: 1, data: 3 },
target: { position: 2, data: undefined },
cost: 1
},
{
operation: 'equal',
source: { position: 2, data: 3 },
target: { position: 2, data: '3' },
cost: 0
}
]
Contributions
To contribute to align-arr, follow these steps:
- Fork this repository.
- Create a branch:
git checkout -b <branch_name>.
- Make your changes and commit them:
git commit -m '<commit_message>'
- Push to the original branch:
git push origin <project_name>/<location>
- Create the pull request.
Alternatively see the GitHub documentation on creating a pull request.
Contributors
Thanks to the following people who have contributed to this project:
Contact
If you want to contact me you can reach me at guy.manzurola@gmail.com.
License
This project uses the following license: MIT.
