Comment-preserving JSON / JSON5 parser
json5-writer provides an API for parsing JSON and JSON5 without losing comments or formatting. It does so by transforming JSON5 into a JavaScript AST and using jscodeshift to update values.
const json5Writer = require('json5-writer')
const config = fs.readFileSync('config.json5', 'utf-8')
const writer = json5Writer.load(config)
writer.write({
'eat honey': { cooldown: 3 },
speak: { cooldown: 2 },
bear: { actions: ['eat honey', 'speak'] },
})
fs.writeFileSync('config.json5', writer.toSource(), 'utf-8')config.json5 diff
{
// actions
'eat honey': {
- cooldown: 4,
+ cooldown: 3,
},
+
+ 'speak': {
+ cooldown: 2,
+ },
// Note: A day without a friend is like a pot without a single drop of honey left inside.
// entities
'bear': {
- actions: [ 'eat honey' ],
- canSpeak: true,
+ actions: ['eat honey', 'speak'],
},
}npm install --save json5-writerconst writerInstance = json5Writer.load(jsonStr) // get a writer instance for the given JSON / JSON5 string
writerInstance.write(objectOrArray) // update jsonStr, preserving comments
const ast = writerInstance.ast // directly access the AST with jscodeshift API
const newJson5 = writerInstance.toSource(options) // get the modified JSON5 string
const newJson = writerInstance.toJSON(options) // get the modified JSON stringUpdates the JSON / JSON5 string with the new value. Any field or property that doesn't exist in value is removed.
To keep an existing value, use undefined:
const writer = json5Writer.load(`[{ name: 'Noah' }, { name: 'Nancy' }]`)
writer.write([{ name: undefined, age: 28 }, undefined ])
write.toSource() // [{ name: 'Noah', age: 28 }, { name: 'Nancy' }]Directly access the JSON5-turned-JavaScript AST, wrapped in the jscodeshift API.
const j = require('jscodeshift')
const writer = json5Writer.load('[1, 2, 3, 4]')
writer.ast.find(j.Literal).forEach(path => {
if (path.value.value % 2 === 0) path.value.value = 0
})
write.toSource() // [1, 0, 3, 0]Get the modified JSON5 string.
options control what is output. By default, single quotes and trailing commas are enabled and key quote usage is inferred.
.toSource({ quote: 'single', trailingComma: true, quoteKeys: undefined })quoteKeyscontrols whether object keys are quoted. It can have three different values:false- no object keys will have quotestrue- all object keys will have quotesundefined- object key quote usage is inferred [default]
quotecan be eithersingleordouble
View the remaining options here.
Same as .toSource(options) but with quote: 'double', trailingComma: false, quoteKeys: true by default.
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