json-placeholder-replacer

jsonPlaceholderReplacer

Lightweight yet really powerful typescript library/cli to replace placeholders in an javascript object/JSON. By default, all you have to do is to use double curly brackets {{placeholderKey}} or angle brackets <<placeholderKey>>, interchangeably, to identify the placeholder. Don't worry, if you don't like these default placeholders you can create your own.

CLI usage

$ json-placeholder-replacer replaceableFilename [...variableMaps]

Example:

$ json-placeholder-replacer replaceable.json variable.map

Would result:

replaceable.json: 
        {
	        "curly": "{{key}}",
        	"angle": "<<key>>"
        }
variable.map: 
        {
                "key": 10
        }
result:
        {
                "curly": 10,
                "angle": 10
        }

Library usage:

As simples as:

import {JsonPlaceholderReplacer} from "json-placeholder-replacer";
const placeHolderReplacer = new JsonPlaceholderReplacer();

placeHolderReplacer.addVariableMap({
    key: 100,
    otherKey: 200
});
const afterReplace = placeHolderReplacer.replace({
    replaceable: "{{key}}",
    otherReplaceableWithSameKey: "<<key>>",
    otherReplaceable: "{{otherKey}}"
})

// afterReplace = {
//    replaceable: 100,
//    otherReplaceableWithSameKey: 100,
//    otherReplaceable: 200
// }

It's possible to replace the default placeholders with some as cool as you want.

const placeHolderReplacer = new JsonPlaceholderReplacer({begin: '@{{-', end: '-}}@'});
placeHolderReplacer.addVariableMap({
    key: "nice"
});
const afterReplace = placeHolderReplacer.replace({
    replaceable: "@{{-key-}}@",
})

// afterReplace = {
//    replaceable: "nice",
// }

It's possible to add more than one variables map.

placeHolderReplacer.addVariableMap({
    firstMapKey: "1"
});
placeHolderReplacer.addVariableMap({
    secondMapKey: 2
});
const afterReplace = placeHolderReplacer.replace({
    replaceable: "{{firstMapKey}}",
    otherReplaceable: "<<secondMapKey>>"
})

// afterReplace = {
//    replaceable: "1",
//    otherReplaceable: 2
// }

And the last added maps have higher priority, so:

placeHolderReplacer.addVariableMap({
    id: "lowerPriority"
});
placeHolderReplacer.addVariableMap({
    id: "higherPriority"
});
const afterReplace = placeHolderReplacer.replace({
    replaceable: "{{id}}"
})

// afterReplace = {
//    replaceable: "higherPriority"
// }

It keeps original variable types. So, if, in the map, a variable is boolean/string/number/object when it's replaced, it remains as boolean/string/number/object:

placeHolderReplacer.addVariableMap({
    booleanKey: true,
    stringKey: "string",
    numberKey: 10,
    objectKey: {
      inner: "inner"
    }
});
const afterReplace = placeHolderReplacer.replace({
    booleanReplaceable: "{{booleanKey}}",
    stringReplaceable: "{{stringKey}}",
    numberReplaceable: "{{numberKey}}",
    objectReplaceable: "{{objectKey}}"
})

// afterReplace = {
//    booleanReplaceable: true,
//    stringReplaceable: "string",
//    numberReplaceable: 10,
//    objectReplaceable: {
//      inner: "inner"
//    }
// }

Just to make it clearer, it does not replace the placeholder Key:

placeHolderReplacer.addVariableMap({
    key: "someValue"
});
const afterReplace = placeHolderReplacer.replace({
    "{{key}}": "value"
})
// afterReplace = {
//    "{{key}}": "value"
// }

And, of course, it handles array substitution as well:

placeHolderReplacer.addVariableMap({
    key: 987,
    objectReplaceable: {
      inner: "inner"
    }
});
const afterReplace = placeHolderReplacer.replace({
    array: ["string", "{{objectReplaceable}}", {{key}}]
})

// afterReplace = {
//    array: ["string", {
//                        inner: "inner"
//                      }, 987]
// }

Want to get nested elements? Go for it!

placeHolderReplacer.addVariableMap({
    key: {
        nested: "value"
    }
});
const afterReplace: any = placeHolderReplacer.replace({
    replaceable: "<<key.nested>>"
});

// afterReplace = {
//    replaceable: "value"
// }