Decompose a javascript object into a set of path/value slices.
npm install pathosDecompose a javascript object into a set of path/value slices.

This module is installed via npm:
`` bash`
$ npm install pathos
Take an object, and convert it to a list of paths and values.
` js
var pathos = require('pathos');
// object to slice up
var o = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyota',
model: 'Camry'
},
{
make: 'Toyota',
model: 'Corolla'
}
]
};
// slice the object
var paths = pathos.slice(o);
// the result is a list of key value pairs, where the keys are the paths and
// the values are the leaves
expect(paths).to.eql(
[ { key: [ 'name' ], value: 'Eugene' },
{ key: [ 'number' ], value: 42 },
{ key: [ 'tags' ], value: [] },
{ key: [ 'tags', '0' ], value: 'tag1' },
{ key: [ 'tags', '1' ], value: 'tag2' },
{ key: [ 'tags', '2' ], value: 'tag3' },
{ key: [ 'cars' ], value: [] },
{ key: [ 'cars', '0', 'make' ], value: 'Toyota' },
{ key: [ 'cars', '0', 'model' ], value: 'Camry' },
{ key: [ 'cars', '1', 'make' ], value: 'Toyota' },
{ key: [ 'cars', '1', 'model' ], value: 'Corolla' } ]);
`
If you have a path, and an object, you can walk the object's path and then
return what is pointed to:
` js
var pathos = require('pathos');
// object to walk
var o = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyota',
model: 'Camry'
},
{
make: 'Toyota',
model: 'Corolla'
}
]
};
// find what is pointed to by the path [ 'cars', '1', 'make' ])
var ret = pathos.walk(o, [ 'cars', '1', 'make' ]);
expect(ret).to.equal('Toyota');
`
If you have a set of paths and values, you can build the object which has the
list of paths and values:
` js
// list of paths and values that define an object
var paths =
[ { key: [ 'name' ], value: 'Eugene' },
{ key: [ 'number' ], value: 42 },
{ key: [ 'tags' ], value: [] },
{ key: [ 'tags', '0' ], value: 'tag1' },
{ key: [ 'tags', '1' ], value: 'tag2' },
{ key: [ 'tags', '2' ], value: 'tag3' },
{ key: [ 'cars' ], value: [] },
{ key: [ 'cars', '0', 'make' ], value: 'Toyota' },
{ key: [ 'cars', '0', 'model' ], value: 'Camry' },
{ key: [ 'cars', '1', 'make' ], value: 'Toyota' },
{ key: [ 'cars', '1', 'model' ], value: 'Corolla' } ];
// re-assemble the object based on paths
var result = pathos.build(paths);
// the re-assembled object should look similar to this
var expected = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyota',
model: 'Camry'
},
{
make: 'Toyota',
model: 'Corolla'
}
]
};
expect(result).to.eql(expected);
`
Given an object, and a path to a field, and a new value to the field, you can
use pathos#set to update it's value:
` js
var pathos = require('pathos');
var o = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyota',
model: 'Camry'
},
{
make: 'Toyota',
model: 'Corolla'
}
]
};
pathos.set(o, [ 'cars', '1', 'make' ], 'Toyoda');
var expected = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyota',
model: 'Camry'
},
{
make: 'Toyoda',
model: 'Corolla'
}
]
};
expect(o).to.eql(expected);
`
Given a function that takes an object path, and its value, the #visit
function will apply a visitor function to each path/value pair:
` js
var pathos = require('pathos');
var o = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyota',
model: 'Camry'
},
{
make: 'Toyota',
model: 'Corolla'
}
]
};
var paths = [];
function visit(key, value) {
paths.push({ key: key, value: value });
}
pathos.visit(o, visit);
expect(paths).to.eql(
[ { key: [ 'name' ], value: 'Eugene' },
{ key: [ 'number' ], value: 42 },
{ key: [ 'tags' ], value: [] },
{ key: [ 'tags', '0' ], value: 'tag1' },
{ key: [ 'tags', '1' ], value: 'tag2' },
{ key: [ 'tags', '2' ], value: 'tag3' },
{ key: [ 'cars' ], value: [] },
{ key: [ 'cars', '0', 'make' ], value: 'Toyota' },
{ key: [ 'cars', '0', 'model' ], value: 'Camry' },
{ key: [ 'cars', '1', 'make' ], value: 'Toyota' },
{ key: [ 'cars', '1', 'model' ], value: 'Corolla' } ]);
});
`
You can write a function that visits every path, value pair in an object
and then optionally remove the path (by returning false), keep the objecttrue
(by returning ) or by changing the property path or value:
#### Rename a field
` js
// rename a field
var pathos = require('pathos');
var o = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyota',
model: 'Camry'
},
{
make: 'Toyota',
model: 'Corolla'
}
]
};
function rename(key, value) {
if (key[key.length - 1] === 'make') {
key[key.length - 1] = 'manufacturer';
return {
key: key,
value: value
};
} else {
return true;
}
}
pathos.rewrite(o, rename);
var expected = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
manufacturer: 'Toyota',
model: 'Camry'
},
{
manufacturer: 'Toyota',
model: 'Corolla'
}
]
};
expect(o).to.eql(expected);
`
#### Change a field's value
` js
var pathos = require('pathos');
var o = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyota',
model: 'Camry'
},
{
make: 'Toyota',
model: 'Corolla'
}
]
};
function change(key, value) {
if (key[key.length - 1] === 'make') {
return {
key: key,
value: 'Toyoda'
};
} else {
return true;
}
}
pathos.rewrite(o, change);
var expected = {
name: 'Eugene',
number: 42,
tags: ['tag1', 'tag2', 'tag3'],
cars: [
{
make: 'Toyoda',
model: 'Camry'
},
{
make: 'Toyoda',
model: 'Corolla'
}
]
};
expect(o).to.eql(expected);
``
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